UC-NRLF 


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arvai 


THE  LIBRARY 

OF 

THE  UNIVERSITY 
OF  CALIFORNIA 

PRESENTED  BY 

PROF.  CHARLES  A.  KOFOID  AND 
MRS.  PRUDENCE  W.  KOFOID 


VIEWS 


MICROSCOPIC   WORLD: 

DESIGNED  FOR  GENERAL  READING,  AND  AS 

A  HAND-BOOK  FOR  CLASSES  IN  NATURAL  SCIENCE. 
BY  JOHN  BROCKLJESBY,  A.  M., 

PROFESSOR  OF  MATHEMATICS  AND  NATURAL  PHILOSOPHY,  IN  TRINITY  COLLEGE,  HABTFORD  ; 
AUTHOR  OF  "THE  ELEMENTS  OF  METEOROLOGY." 


toorka  pr 

ILLUSTRATED  WITH    NUMEROUS  ENGRAVINGS  AND   DRAWINGS. 


NEW  YORK : 

PRATT,    WOODFORD    &    COMPANY. 
NO.  4  COURTLANDT-STREET. 

1851. 


EKTKEKD,  according  to  Act  of  Congress,  in  the  year  One  Thousand  Eight  Hundred  and  Fifty, 

BY  JOHN  BROCKLESBY, 
In  the  Clerk's  Office  of  the  District  Court  of  Connecticut 


6.i* 

\o  t^y 


CONTENTS. 


PAGE. 

PREFACE, 3 

INTRODUCTORY  CHAPTER, 5 

Microscope, 8 

Single  Microscope, " 

Compound  Microscope, 9 

Solar  Microscope 13 

CHAPTER  I. 

INFUSORIAL   ANIMALCULES. 

Structure, 17 

Classification, 19 

Polygastrica, " 

Rotatoria, 20 

Eyes, 21 

Reproduction, " 

Life  and  Resuscitation, 22 

Influence  of  Temperature, 23 

Air, 24 

Poisons, " 

Phosphorescence  of  the  Sea, " 

Colored  Tracts  of  the  Ocean, 26 

POLYGASTRIC   ANIMALCULES, 27 

Monads, " 

Twilight  Monad, " 

Great  Monad, 28 

The  Green  Eye-Monad, " 

The  Breast-plate  Animalcules, " 

The  Revolving  Globe- Animalcule, 30 

The  Ray-Globe  Animalcules, 32 

The  Blood-like  Astatia, " 

the  Blood-red  Eye  Animalcule " 

The  Flowering-cup  Animalcules, 33 

The  Proteus 34 

Bacillaria,  or  Stick  Animalcules, " 

The  Gallionella,  or  Box-chain  Animalcules,  35 

The  Striped  Gallionella, " 

The  Rust-like  Gallionella, 36 

The  Navicula,  or  Little-Ship  Animalcules,  " 

.Green  Navicula, " 

1 


PAGE. 

Golden  Navicula, 37 

The  Swollen  Eunotia, " 

Xanthidia,  or  Double-bar  Animalcules,.. ..  38 

The  Pyxidicula,  or  Round-box  Animalcules,  " 

Zigzag  Animalcules, 39 

The  Palm  Fan-shaped  Animalcule, 39 

The  Bell-shaped  Animalcules, 40 

The  Tree- Animalcules, 42 

Trumpet  Animalcules, 43 

Purse  Animalcule, 45 

WHEEL-ANIMALCULES,  OR  ROTATOKIA, " 

The  Common  Wheel- Animalcule, " 

The  Crown  Wheel- Animalcule,  or  Stepha- 

noceros, 47 

The  Beaded-Melicerta,  or  Four-leaved  Ani- 
malcule,. . . ., 49 

The  Hornwort  Limnias,  or  Water  Nymph,  52 

The  Elegant  Flower-shaped  Animalcule,. . .  " 

CHAPTER  II. 

FOSSIL   INFUSORIA. 

Fossil  Animalcules  of  Chalk  and  Flint,.. . .  56 

Peat  Bogs, 59 

Foraminifera, " 

Mud-Banks 51 

Infusorial  Dust, 63 

CHAPTER  III. 

MINUTE   AQUATIC   ANIMALS. 

The  Polype, 65 

The  Round  Lynceus,  or  Monoculus, 69 

The  Small  Water-Flea, 70 

The  Vaulter, 71 

The  Larva  of  a  small  Boat-Fly, 71 

The  Larva  of  a  species  of  Water-Beetle,.  72 

The  Lurco,  or  Glutton, 74 

Eels  in  Paste, 75 

The  Vinegar  Eel, 76 


15761 


CONTEXTS. 


CHAPTER  IV. 


PAGE. 


OF  THE  STRUCTURE  OF  WOOD  AND  HERBS. 

Woody  Portion, 

Arrangement, 

Cellular  Tissue, 

Pith, 

Wood  and  Woody  Texture, 

Bark, 

The  Mode  of  Growth  in  the  Trunk  and 

Branches  of  Trees, 

SECTIONS  OF  WOOD, 

The  Holly, 

Pear  Tree, 

The  Hazel, 

English  Oak, 

White  Oak, 

Elm, 

English  Walnut, 

Ash  Branch, 

Maple, 

Dogwood, 

White  Pine, 

Mallaca, 

Whitewood, 

Sumach, 

Wormwood, 

Root  of  Wormwood, 

FOSSIL  WOODS  AND  PLANTS, 

Coal, 


CHAPTER  V. 

CRYSTALLIZATIONS. 

Nitrate  of  Potash,  or  Saltpetre, 101 

Flowers  of  Benzoin, 102 

Sulphate  of  Iron,  or  Copperas, 103 

Camphor, " 

Sal  Ammoniac,  or  Muriate  of  Ammonia,..  104 

Muriate  of  Barytes, « 


PAGK- 

Bichromate  of  Potassa, 105 

Sulphate  of  Soda,  or  Glauber  Salts, 106 

Verdigris, 107 

Sulphate  of  Magnesia,  or  Epsom  Salts, ...     " 

Sulphate  of  Copper, 108 

Alum 109 

Salt,  or  Chloride  of  Sodium, « 

Snow, " 

ON  CRYSTALS  FOUND  IN  PLANTS, Ill 

CHAPTER  V. 

PARTS  OF  INSECTS  AND  MISCELLANEOUS  OBJECTS. 

Eyes, 116 

Reticulated  Eyes, 117 

Wings, 120 

Hemerobius  Perla, 122 

Feathers  of  Moths  and  Butterflies, " 

Eggs 125 

Hairs, " 

The  Proboscis  of  the  Ox-Fly, 127 

The  Sucker  of  the  Gnat, " 

The  Proboscis  of  the  Bee, 128 

Sting  of  the  Wild  Bee, 130 

Feet, " 

Antennee, 132 

Scales  of  Fishes, 133 

The  Internal  Organs  of  Respiration  of  the 

Silk-Worm, 136 

Magnified  Flea, 138 

A  Mite  Magnified, 140 

Globules  of  Blood, « 

The  Web  of  the  Frog's  Foot, 142 

Pollen, 143 

Indian  Corn, 144 

Fuschia, 145 

Sweet  Pea, " 

Fern  Seed, * 


PREFACE. 


To  those  who  have  had  the  command  of  accurate  and  powerful  instruments,  the  field  of 
microscopic  research  has  ever  been  one  of  delightful  labor.  Nearly  in  every  direction,  in  which 
their  investigations  have  been  prosecuted,  new  and  surprising  discoveries  have  rewarded  their 
diligence  and  zeal,  while  glimpses  of  others  no  less  amazing  have  allured  them  onward  in  their 
pleasing  path. 

But  the  wondrous  scenes  thus  revealed  to  the  eye  have  hitherto  been  mostly  confined  to  this 
favored  class ;  they  have  indeed  faithfully  delineated  the  curious  living  and  extinct  forms,  and 
the  beautiful  configurations  which  have  met  their  view,  and  have  likewise  fully  recorded  the 
observations  they  have  made  upon  these  interesting  objects,  but  the  productions  of  their  pencil 
have  for  the  most  part  been  enshrined  in  rare  and  costly  volumes,  and  they  have  seldom 
spoken  but  in  the  dignified  language  of  science.  Thus  it  has  happened,  that  of  the  many 
eager  and  inquiring  minds,  which  love  to  expatiate  in  the  fields  of  Nature,  a  few  only  have 
enjoyed  the  privilege  of  exploring  the  inner  labyrinths  of  creation,  and  of  gathering  from 
thence  new  treasures  of  wisdom  and  knowledge. 

When,  by  the  mighty  power  of  the  telescope,  the  astronomer  was  first  enabled  to  gaze  into 
space,  as  with  the  ken  of  an  angel,  and  to  recognise  the  orbs  that  glittered  in  the  firmament  as 
worlds  like  our  own,  countless  in  number,  and  stretching  away  through  widening  circles  in  all 
the  vastness  and  magnificence  of  infinitude ;  Infidelity  advanced  once  more  to  the  attack, 
and  argued  against  Revelation  from  the  immensity  of  creation  ;  affirming  that  man  was  too 
insignificant  a  creature  to  be  the  peculiar  care  of  Him,  who  had  filled  the  illimitable  regions  of 
space  with  such  stupendous  works. 

Baseless  as  this  argument  is,  it  is  nevertheless  calculated  to  exert  a  pernicious  influence 
upon  unstable  minds ;  since  to  good  men,  whose  faith  has  never  wavered,  the  condescension 
of  the  Supreme  Being,  in  regarding  man  at  all,  has  ever  appeared  unutterably  amazing.  Lit- 
tle was  known  of  the  glories  of  the  universe  in  the  age  of  the  Psalmist,  yet  even  he  breaks  forth 
into  the  following  strain  of  wonder,  as  he  lifts  his  eyes  to  the  sparkling  sky :  "  "When  I  consider 
thy  heavens,  the  work  of  thy  fingers ;  the  moon  and  the  stars,  which  thou  hast  ordained ;  what  is 
man  that  thou  art  mindful  of  him  ?" 

Now  the  microscope  has  not  only  turned  aside  this  blow  of  the  scoffer,  but  caused  it  to  recoil 
upon  himself;  for  by  the  aid  of  this  instrument  we  follow  the  footsteps  of  Divinity,  into  fields 
of  creation  so  inconceivably  small,  that  man,  compared  with  them,  is  a  universe  in  respect  to 


4  PREFACE. 

magnitude.  Yet  here  we  trace  the  workings  of  Infinite  benevolence,  as  visibly  impressed  on 
minute  forms  and  organizations,  as  in  the'  starry  vault,  emblazoned  upon  its  rolling  worlds. 
Here  we  learn  with  new  force  the  harmony  of  Nature  with  Revelation,  and  how  true  it  is, 
"  that  a  sparrow  shall  not  fall  to  the  ground  without  our  Father." 

Influenced  by  these  considerations,  I  have  been  led  to  believe,  that  a  popular  work  upon  the 
revelations  of  the  microscope  might  at  once  be  interesting  and  useful.  This  belief  has  resulted 
in  the  present  little  treatise,  which  does  not  profess  to  be  a  panorama  of  the  microscopic 
world,  but  simply  an  exhibition  and  description  of  some  of  its  most  rare  and  curious  objects. 

In  the  preparation  of  this  volume,  liberal  use  has  of  course  been  made  of  the  discoveries  of 
the  distinguished  Ehrenberg,  without  which  it  must  necessarily  have  been  very  defective.  I 
have  also  drawn  copiously  from  the  writings  of  Grew,  Adams,  Pritchard,  Mantell  and  others ; 
and  from  these  sources  the  greater  part  of  the  illustrations  have  also  been  obtained.  Without 
specifying  other  portions  of  the  book,  the  chapter  on  the  crystallization  of  salts  (except  the 
remarks  upon  snow)  is  the  result  of  my  own  observations,  and  the  drawings  it  contains  are  repre- 
sentations of  actual  crystallizations,  seen  and  studied  by  the  artist.  Besides  these  delineations, 
many  other  original  drawings  and  cuts  are  scattered  throughout  the  work.  The  frontispiece  is 
an  accurate  representation  of  one  of  Chevalier's  microscopes,  which  I  have  employed  in  all  my 
researches.  The  original  drawings,  as  well  as  the  copies  of  the  selected  cuts,  were,  for  the 
most  part,  executed  by  Mr.  W.  R.  Lawrence,  a  young  artist  of  this  city,  to  whose  taste  and  skill 
I  am  much  indebted. 

HARTFORD,  Nov.  4th,  1850. 


VIE¥S  OF  THE  MICROSCOPIC  WORLD. 


INTRODUCTORY   CHAPTER. 

"  The  one  told  me  of  the  insignificance  of  the  world  I  tread  upon.  The  other  redeems 
it  from  its  insignificance ;  for  it  tells  me  that  in  the  leaves  of  every  forest,  and  in  the  flowers 
of  every  garden,  and  in  the  waters  of  every  rivulet,  there  are  worlds  teeming  with  life,  and 
numberless  as  are  the  glories  of  the  firmament.  The  one  is  constantly  widening  the  circle  of 
His  territory.  The  other  is  as  constantly  filling  up  its  separate  portions  with  all  that  is  rich, 
and  various,  and  exquisite." — Chalmers. 

SCIENCE  has  presented  the  world  with  two  most  noble  instruments,  which 
will  ever  be  ranked  among  the  proudest  triumphs  of  the  intellect  and  skill  of 
man — the  telescope  and  microscope.  The  thousand  combinations  of  machinery 
that  stand  in  the  work-shops  of  art,  and  seem  to  be  almost  gifted  with  intelli- 
gence, so  perfectly  do  they  perform  their  appointed  tasks,  are  at  the  best  but 
instruments  by  which  we  subject  to  our  use  powers  and  agencies  long  since 
known.  Through  their  means  we  can  apply  to  new  purposes  and  new  ends  the 
resources  that  mankind  have  possessed  for  ages,  and  subdue  the  physical  world 
to  ourselves ;  but  they  are  powerless  to  extend  the  limits  of  our  knowledge,  or 
unfold  one  page  in  the  bright  volume  of  creation,  ever  mirroring  the  glorious 
attributes  of  Divinity.  The  portion  of  the  universe  with  which  we  are  con- 
versant, is  as  large  without  them  as  with  them ;  they  add  no  new  regions  to  the 
field  of  knowledge,  nor  reveal  to  our  astonished  gaze  worlds  and  existences, 
curious  organizations,  harmonies  and  forms  of  beauty  hitherto  unknown. 

Not  so  with  the  telescope  and  microscope ;  they  have  a  higher  office  to  fulfil, 
and  are  rather  the  companions  than  the  slaves  of  man,  ministering  to  the  de- 
mands of  his  mind  and  not  to  the  wants  of  his  body.  They  accompany  the 
flight  of  genius  in  its  glorious  imaginings,  and  often  enable  it  to  give,  to  what 
may  appear  to  others  a  wild  and  visionary  conception,  a  reality  and  permanence 
as  enduring  as  the  universe  itself;  or  they  may  take  the  lead,  and  on  a  sudden 
dazzle  the  beholder  with  visions  of  such  rare  magnificence  and  beauty,  that 
truth  surpasses  fiction,  and  the  fairy  dreams  of  imagination  are  more  than 
realized. 


VIEWS    OF    THE    MICROSCOPIC    WORLD. 

By  their  means  the  boundaries  of  knowledge  are  extended ;  but  the  aid  that 
each  affords  is  essentially  different.  The  telescope  reveals  creations  that  lie  be- 
yond our  globe ;  the  microscope  those  that  are  within  it,  yet  too  minute  to  be 
seen  by  the  unassisted  eye.  The  former  tells  us  of  the  nature  and  motions  of 
the  starry  host  which,  in  their  silent  march  from  century  to  century,  have  "  never 
fainted  in  their  watches/'  and  still  beam  upon  us  in  all  their  primeval  radiance 
and  beauty — the  only  unchanging  objects  upon  which  the  eye  of  man  can  rest. 

It  tells  us  that  they  are  worlds,  and  suns,  and  systems  of  suns  like  our  own, 
rushing  with  inconceivable  speed  through  the  illimitable  fields  of  space ;  the  su- 
perior orbs  moving  in  the  midst  of  a  glittering  zone  of  attendant  worlds,  yet 
each  advancing  in  a  fixed  but  invisible  path,  and  guided  by  laws  as  immutable 
as  the  word  of  Him  who  made  them.  At  every  progressive  step  the  revelations 
become  more  amazing,  and  scenes  after  scenes  of  mysterious  grandeur  are  suc- 
cessively unfolded ;  but  at  the  utmost  verge  of  discovery  we  are  still  upon  the 
threshold  of  creation,  glimpses  only  of  the  infinite  are  beheld,  and  far  as  the 
loftiest  mind  may  soar,  it  perceives  but  a  hand-breadth  of  the  splendid  pano- 
rama of  the  skies. 

The  microscope,  in  its  revelations,  advances  in  an  opposite  direction — from  the 
infinite  in  extent  to  the  infinitely  small.  Tt  places  us  in  the  midst  of  a  world 
before  invisible,  which,  like  a  new  creation  in  the  freshness  of  beauty,  stretches 
away  in  enchanting  prospects  on  every  side.  Far  as  our  assisted  sight  may 
pierce,  all  is  instinct  with  life,  enshrined  in  strange  and  curious  forms,  and 
replete  with  harmony,  and  skill,  and  wise  design.  And  our  discoveries  terminate 
not  for  the  want  of  unknown  fields  to  explore,  full  of  the  developments  of  creative 
power,  but  because  our  sight  grows  dim,  and  we  have  no  further  means  of  pour- 
ing light  upon  what  remains  unseen,  and  dispelling  the  darkness  that  rests  upon 
the  surrounding  regions  of  infinitude. 

Under  this  noble  instrument  the  most  common  substances  and  objects  are  fre- 
quently sources  of  the  highest  interest  and  instruction :  a  grain  of  marl  or  pow- 
dered rock  is  seen  to  consist  almost  entirely  of  the  flinty  shells  of  minute  animals, 
which  ages  ago  sported  in  the  full  activity  of  life,  and  have  left  the  enduring 
records  of  their  existence  accumulated  in  mountains,  and  deposited  through  the 
deep  soil  of  wide-spread  plains.  The  rock  and  the  soil  have  not  simply  entombed 
these  shells,  but  their  minute  forms,  so  small  that  millions  are  frequently  com- 
pressed within  a  cubic  inch,  constitute  the  chief  material  of  these  mountains 
and  plains.  Rocks  are  quarried  from  their  aggregated  myriads,  and  upon  them 
are  based  the  solid  edifices  of  large  and  stately  cities. 

Let  the  scene  be  varied.  A  thin  slice  of  the  bark  or  wood  of  the  most 
common  tree  is  placed  beneath  the  microscope  ;  a  moment  before  there  was  no- 
thing in  its  appearance  to  attract  attention ;  now  a  most  beautiful  organization  is 
before  us,  and  ranges  of  cells  and  tubes  are  seen  grouped  in  symmetrical  figures, 
and  forming  a  delicate  tissue,  surpassing  in  the  fineness  of  its  texture  the  richest 
lace.  Or  should  the  unbroken  ashes  of  a  leaf  be  examined,  the  structure  is 
perceived  to  be  still  in  existence,  the  minute  veins  of  the  leaf  running  in  various 


INTRODUCTORY    CHAPTER.  7 

directions,  and  tracing  over  its  whole  surface  an  exquisite  net-work  of  glittering 
crystals ;  for  every  line  and  vein  consist  of  rows  of  crystalline  particles,  and 
within  the  compartments  formed  by  these  intersections  other  vegetable  gems 
sparkle  in  the  light. 

The  prospect  may  be  again  changed,  and  the  minute  parts  of  insects  brought 
within  the  range  of  t\e  instrument,  when  new  manifestations  of  the  riches  of 
creation  are  at  once  beheld.  It  is  then  seen  that  these  living  atoms  display  in 
their  structure  the  skill,  wisdom,  and  benevolence  of  their  Creator,  equally  with 
those  which  exceed  them  in  bulk,  millions  of  times.  In  the  construction  and 
adaptation  of  their  members,  there  is  the  same  evidence  of  useful  design ;  and 
beauty,  with  all  its  manifold  adornments,  has  been  showered  upon  them  with  a 
lavish  hand.  The  radiant  bird  of  the  tropics,  in  the  pride  of  its  plumage,  is 
surpassed,  both  in  the  exuberance  of  its  splendor,  and  the  perfection  of  its  struc- 
ture, by  insects  that  are  thoughtlessly  crushed  beneath  our  feet ;  or  by  those 
which,  sporting  in  the  sunbeams  for  a  few  short  days,  pass  through  the  whole 
course  of  their  existence.  The  microscope  is  also  a  powerful  auxiliary  to  the 
skilful  physiologist  in  his  researches  into  the  hidden  mysteries  of  the  vital  sys- 
tem. And  by  this  means,  within  a  few  years,  much  valuable  information  has 
been  gained  in  regard  to  the  curious  processes  of  life,  and  of  the  organization 
and  wondrous  mechanism  of  the  human  body. 

Another  scene  may  be  yet  unfolded,  and  one  which  gives  the  microscope  a 
superior  importance  when  compared  with  the  telescope.  The  wonders  revealed 
by  the  latter  are  indeed  so  sublime,  that  they  can  hardly  be  grasped  by  the  hu- 
man intellect,  and  mysteriously  do  they  shadow  forth  the  majesty  and  power  of 
God.  Yet  throughout  the  whole  field  of  magnificent  display,  nothing  is  seen 
but  inanimate  matter,  obeying  the  laws  impressed  upon  it  by  Him  who  called  all 
things  into  being.  Not  so  when  the  student  of  nature  ranges  with  the  micro- 
scope amid  minute  material  forms,  and  sweeps  over  a  drop  of  water  with  his 
powerful  glasses,  as  the  astronomer  on  a  cloudless  night  sweeps  with  his  telescope 
across  the  starry  heavens.  The  drop  at  once  becomes  a  sea,  teeming  with 
life,  and  curious  forms  are  seen,  stranger  "  than  fables  e'er  have  feigned  or  fear 
conceived,"  sporting  at  will  through  its  spacious  waters. 

The  world  just  revealed,  is  indeed  a  world  of  wonders,  for  the  singular  beings 
before  us  bear  no  resemblance  to  those  which  are  visible  to  the  unaided  eye,  and 
their  modes  of  progression,  existence,  and  increase,  are  in  most  respects  entirely 
dissimilar.  But  life  with  its  rich  endowments  is  theirs,  and  though  millions  can 
be  contained  within  the  bulk  of  a  mustard-seed,  yet  each  individual  of  this  vast 
assemblage  is  as  perfect  in  its  organization  as  an  elephant,  which  in  its  relative 
size  to  this  sentient  atom,  resembles  a  universe  compared  with  ourselves.  The 
living  beings,  within  the  limits  of  the  microscopic  world,  are  probably  far  more 
numerous  than  those  which  are  perceptible  to  the  naked  eye.  And  from  the 
splendid  discoveries  that  have  been  made,  it  is  no  stretch  of  fancy  to  imagine, 
but  the  sober  dictate  of  reason  to  infer,  that  if  our  vision  could  be  rendered  more 
and  more  piercing,  and  progressively  advance  from  the  minutely  visible,  through 


VIEWS    OF    THE    MICROSCOPIC    WORLD. 

the  successive  realms  of  the  invisible,  exploring  onward  towards  the  inner  shrine 
of  nature ;  that  new  scenes  of  beauty  would  continually  unfold,  and  new  fields 
of  Omniscient  display  would  be  constantly  revealing,  that  God  was  still  before  us 
in  his  creative  energy,  that  we  saw  "  but  the  hidings  of  his  power."  And  as  we 
traced  our  steps,  back  to  the  visible  through  all  the  glorious  realms  that  had  been 
brought  to  light,  we  should  feel  the  truth,  that  this  outer  world  is  but  the  casket 
in  which  the  riches  of  creation  are  enshrined. 

THE   MICROSCOPE. 

Before  we  proceed  to  describe  the  wonders  and  beauties  revealed  by  the 
Microscope,  it  appears  not  only  desirable  but  highly  important,  that  the  instru- 
ment itself  should  be  well  understood,  and  the  optical  principles  involved  in  its 
construction  firmly  fixed  in  the  mind.  And  for  the  obvious  reason,  that  an  intel- 
ligent mind  not  only  wishes  to  be  acquainted  with  results,  but  also  with  the 
means  and  processes  by  which  those  results  are  obtained ;  for  if  it  is  possessed 
of  the  results  only,  it  is  dependent  for  the  truth  or  falsity  of  its  information  sim- 
ply upon  the  credit  due  to  its  instructor  for  honesty  and  accuracy ;  but  when  each 
step  from  the  beginning  to  the  end  is  tested  by  the  judgment,  and  everything 
rejected  that  bears  not  the  stamp  of  truth,  knowledge  then  becomes  doubly  valua- 
ble, and  the  conclusions  that  are  presented  are  then  received  not  with  a  lukewarm 
and  faint  assent,  but  are  at  once  embraced  in  full  and  undoubted  confidence. 

In  the  subject  before  us  it  is  peculiarly  requisite  that  the  reader  should  know 
the  capacities  of  the  instrument,  which  introduces  him  into  such  new  and  surprising 
scenes  amid  the  fields  of  creation;  inasmuch  as  the  objects  with  which  it  deals 
are  so  minute,  that  although  their  dimensions  can  be  ascertained  with  very  great 
precision,  yet  a  person  unacquainted  with  the  power  of  the  Microscope  would  be 
much  disposed  to  receive  the  actual  measurements  of  objects  with  some  dis- 
trust, regarding  them  only  as  broad  approximations  towards  the  truth  ;  ingenious 
indeed,  but  mere  guesses  at  the  best. 

SINGLE  MICROSCOPE. — An  object  is  rendered  visible  by  rays  of  light,  which 
emanating  from  points  on  its  surface,  are  received  by  the  eye  and  concentrated 
upon  the  retina,  in  points  corresponding  in  relative  position  to  those  from  which 
they  proceeded,  thus  forming  a  distinct  image  upon  the  inner  posterior  surface 
of  the  eye.  In  the  eyes  of  most  persons,  no  such  image  can  be  formed  when  the 
object  is  brought  nearer  to  the  organ  than  the  distance  of  Jive  inches,  inasmuch 
as  the  rays  proceeding  from  the  object  then  diverge  so  much  that  the  eye  is  un- 
able to  concentrate  them  to  their  appropriate  points  upon  the  retina,  and  the  . 
object  then  becomes  indistinct  and  the  outline  confused.  If,  however,  a  trans- 
parent medium  of  a  proper  form  is  interposed  between  the  eye  and  the  object, 
when  the  latter  is  nearer  the  organ  than  the  distance  of  five  inches,  the  direction 
of  the  rays  of  light  may  be  so  changed  that  the  perfect  action  of  the  eye  is  again 
restored  and  the  object  clearly  discerned.  Such  a  medium  is  a  convex  lens, 


INTRODUCTORY    CHAPTER.  9 

which  is  usually  made  of  glass.  If  one  side  of  a  convex  lens  is  presented  to  the 
parallel  rays  of  the  sun,  they  are  made  to  converge  on  the  other  side  to  a  single 
point,  called  the  focus,  as  is  easily  seen  by  receiving  them  upon  a  piece  of  paper, 
placed  at  a  proper  distance  from  the  centre  of  the  lens.  This  distance  is  called 
the  focal  distance  of  the  lens.  On  the  other  hand,  if  an  object  is  placed  in  this 
focus,  the  rays  of  light,  which  proceed  from  it  and  fall  diverging  upon  the  nearest 
side  of  the  lens,  emerge  parallel  on  the  other  side,  and  if  they  are  then  received 
by  the  eye  the  object  is  clearly  seen.  Now  it  is  found  that  the  apparent  length 
and  breadth  of  an  object  is  magnified  by  such  an  arrangement,  in  the  ratio  of  the 
limit  of  distinct  vision  to  the  focal  distance  of  the  lens.  Thus,  if  the  limit  of  dis- 
tinct vision  is  Jive  inches,  and  the  focal  distance  of  a  lens  through  which  the 
object  is  viewed  one  inch,  the  object  will  be  seen  Jive  times  nearer  than  by  the 
naked  eye,  and  will  be  magnified  Jive  times  both  in  length  and  breadth ;  and  its 
surface  will  be  increased  in  apparent  size  twenty-Jive  times.  Single  lenses  of 
garnet  have  been  executed  of  very  small  focal  distances.  Two  of  this  kind  are 
in  the  possession  of  Sir  David  Brewster,  the  focal  lengths  of  which  are  between 
one-thirtieth  and  one-fiftieth  of  an  inch.  A  Figure  i. 

lens  with  a  focal  distance  of  one-fiftieth  of  an 
inch  would  magnify  an  object  linearly  two 
hundred  and  fifty  times,  and  superficially, 
sixty-two  thousand  five  hundred  times.  Such 
a  lens  as  has  been  described  is  termed  a  Sin- 
gle Microscope,  and  is  represented  by  Figure  1, 
where  A  B  is  the  lens,  C  D  an  object  placed 
in  the  principal  focus  of  the  lens,  at  the  dis- 
tance H  I,  and  E  F  the  magnified  image  seen 
at  the  distance  of  distinct  vision  by  the  eye 
at  N.  The  image  exceeds  the  object  in 
length  and  breadth  as  much  as  N  K  is  larger 
than  H  I. 

COMPOUND  MICROSCOPE. — However  valuable  the  Single  Microscope  may  be, 
to  the  scientific  observer  in  many  cases,  it  is  not  possessed  of  sufficient  power 
to  reveal,  in  their  perfect  developments,  the  more  minute  objects  of  his  investi- 
gations, and  for  this  purpose  the  Compound  Microscope  is  employed.  The  two 
essential  parts  of  this  instrument  are  an  object-glass  and  an  eye-glass.  The  office 
of  the  object-glass  is  to  produce  a  magnified  image  of  the  object,  which  ima^e 
is  again  magnified  by  viewing  it  with  the  eye-glass,  as  if  it  was  an  object :  the 
eye-glass  being  in  fact  a  single  Microscope.  An  image  is  formed  by  the  object- 
glass  in  the  following  manner  : 

The  object  to  be  magnified  is  placed  a  little  beyond  the  focus  of  parallel  rays, 
for  if  the  object  were  placed  exactly  in  this  focus,  the  rays  proceeding  from  any 
point  on  its  surface  would  emerge  parallel  to  each  other  on  the  opposite  side  and 
never  meet ;  but  by  placing  the  object  a  little  beyond  the  focus,  the  rays  con- 


10 


VIEWS    OF    THE    MICROSCOPIC    WORLD. 


verge  accurately  on  the  other  side  of  the  lens  to  points  corresponding  to  those 
whence  they  proceeded,  and  thus  form  an  image.     This  is  seen  by  a  glance  at 
Figure  2.  Figure  2,  where  E  D  represents  a 

lens,  R  L  its  focal  distance,  ABC 
an  object  placed  a  little  farther  from 
the  lens  than  its  focal  distance,  and 
F  G  H  an  image  of  the  object  on  the 
opposite  side  of  the  lens.  From  the 
point  of  the  arrow  at  C  the  rays 
C  E,  C  L,  and  C  D,  proceed,  which 
are  refracted  to  the  same  point  at  F, 
and  there  combine  to  form  an  image 
of  the  point. 

What  is  true  of  the  rays  emanat- 
ing from  the  point  C,  is  likewise  true 
of  those  proceeding  from  every  point  on  the  surface  of  the  object  directed 
towards  the  lens :  each  converge  on  the  opposite  side  of  the  lens  to  correspond- 
ing points  in  the  image.  The  linear  magnifying  power  of  the  object-glass  is  esti- 
mated according  to  the  following  rule,  that  the  length  or  breadth  of  the  object 
bears  the  same  relation  to  the  length  or  breadth  of  the  image,  as  the  distance  of 
the  object  from  the  centre  of  the  lens  does  to  the  distance  of  the  image  from  the 
centre.  Thus,  if  the  object  is  six  inches  from  the  centre  and  the  image  six  feet, 
it  is  magnified  in  length  and  breadth  twelve  times,  and  the  surface  of  the  object 
is  magnified  twelve  into  twelve,  or  one  hundred  and  forty-four  times. 

Figure  3.  To  illustrate  from  the  figure ;  the  length 

and  breadth  of  the  image  F  H,  exceeds 
the  length  and  breadth  of  the  object,  as 
many  times  as  the  line  B  L  is  contained 
in  the  line  G  L.  The  mode  in  which  an 
object  is  magnified  by  the  Compound 
Microscope  is  shown  in  Figure  3,  where 
A  B  represents  the  object,  D  C  the  object- 
glass,  and  F  E  the  image  of  the  object 
formed  by  the  object-glass,  so  situated 
as  to  be  in  the  principal  focus  of  the  eye- 
glass G  H.  By  this  lens  the  divergent 
rays  of  light  proceeding  from  the  image 
F  E,  have  their  direction  so  changed,  that 
entering  the  eye  on  the  side  of  the  lens  G  P  H,  a  second  magnified  image  is 
clearly  Discerned  at  K  L,  at  the  limit  of  distinct  vision.  The  entire  magnifying 
power  of  the  instrument  is  equal  to  the  combined  effect  of  the  two  glasses,  and  is 
estimated  as  follows  :  The  image  F  E,  is  as  much  larger  than  the  object  A  B,  as 
its  distance  from  the  centre  of  the  object-glass  C  D,  exceeds  the  distance  of  A  B 
from  the  same  point ;  and  the  image  K  L,  is  as  many  times  greater  than  F  E,  as 


INTRODUCTORY    CHAPTER.  11 

the  limit  of  distinct  vision  exceeds  the  principal  focal  distance  of  the  lens  G  H. 
Thus,  if  the  object  A  B,  is  within  half  an  inch  of  the  centre  of  the  lens,  and  the 
image  F  E  is  formed  at  the  distance  of  twelve  inches,  the  linear  magnifying 
power  of  the  object-glass  is  twenty-four ;  and  the  superficial  magnifying  power 
24x24,  or  five  hundred  and  seventy-six.  If  now,  this  image  is  distant  from 
the  centre  of  the  eye-glass  G  H,  one  quarter  of  an  inch,  and  the  limit  of  distinct 
vision  is  five  inches,  the  linear  magnifying  power  of  the  eye-glass  is  twenty,  and 
the  superficial  magnifying  power  20  X  20,  or  four  hundred.  The  entire  linear  mag- 
nifying power  is,  therefore,  expressed  by  24X20,  equalling  480,  and  the  superfi- 
cial magnifying  power  by  576X400,  or  230,400.  The  image  F  E  is,  therefore, 
twenty-four  times  longer  and  broader  than  the  object  A  B,  and  its  surface  five 
hundred  and  seventy-six  times  greater — while  the  length  and  breadth  of  the 
image  K  L,  are  twenty  times  greater  than  the  like  dimensions  of  F  E,  and  its  sur- 
face four  hundred  times  greater.  Comparing  then  the  second  image  K  L,  with 
the  object  A  B,  the  length  and  breadth  of  the  former  are  480  times,  (24X20,) 
greater  than  the  length  and  breadth  of  the  latter,  and  the  surface  of  A  B  is  contained 
in  that  of  K  L  two  hundred  and  thirty  thousand  four  hundred  times,  (576  X  400.) 

When  a  minute  object  is  thus  highly  magnified  the  whole  of  its  surface  can- 
not be  seen  at  once,  but  only  a  small  portion  of  it,  and  that  extent  of  surface 
which  is  visible  at  one  time  is  called  the  field  of  view.  Such  is  the  Compound 
Microscope  in  its  most  simple  form,  and  thus  constructed  it  always  possesses 
many  serious  and  fatal  defects.  These  have  only  been  removed  by  the  aid  of 
complicated  arrangements,  based  upon  the  most  refined  scientific  principles,  and 
executed  with  consummate  skill. 

The  Compound  Microscope  has  thus  at  length  attained  a  very  high  degree  of 
perfection,  and  for  the  sake  of  instruction  we  shall  describe  the  Microscope  of  M. 
Chevalier,  a  French  optician  of  distinguished  ability.  In  Figure  4,  an  outline 
is  presented  of  the  parts  Figure  4. 

which  are  employed  in 
magnifying  the  object,  and 
in  Figure  5,  (frontispiece,) 
the  complete  instrument  is 
delineated.  In  Figure  4, 
B  R  A  is  the  object,  and 
0  P  the  object-glass.  The 
rays  of  light,  proceeding 
through  this  lens  from  the 
object,  fall  upon  glass 
prism  C  D  F,  in  such  a 
manner  that  they  are  to- 
tally reflected  from  the  in- 
clined surface  C  E  F,  and 
emerging  from  the  side 
C  D,  fall  upon  the  lens 
G  V  H ;  the  two  central 


12  VIEWS    OF    THE    MICROSCOPIC    WORLD. 

rays  R  E  and  V  E,  making  at  E  a  right  angle  with  each  other.  By  the  aid 
of  the  lens  G  V  H,  the  image  of  the  object  is  formed  at  S  T,  nearer  the  prism 
than  it  would  be  if  this  lens  was  not  employed.  The  image  S  T  is  still  further 
magnified  by  the  eye-glass  K  I,  causing  the  production  of  the  second  and  last 
image  M  N,  seen  at  the  distance  of  distinct  vision  from  the  eye. 

In  Figure  5,  a  view  of  the  instrument  is  seen  with  its  various  adjustments. 
A  B  is  a  brass  pillar  surmounted  by  a  brass  crosspiece  N.  Upon  the  top  of  this 
the  main  tube  C  D,  of  the  instrument  is  fastened,  to  which  is  attached  a  smaller 
tube  E  F.  At  the  opposite  extremity  is  a  compound  eye-piece  H,  which  is 
screwed  into  the  end  of  an  inner  tube  G,  that  slides  easily  within  the  main  cylin- 
der by  means  of  rack-work  moved  by  a  toothed  axle,  the  head  of  which  is  seen 
at  K.  Eye-pieces  of  different  powers  are  provided,  each  of  which  is  fitted  to  the 
inner  tube.  To  the  horizontal  cylinder  E  F,  a  small  tube  L,  is  attached  at  right 
angles,  into  the  lower  end  of  which  is  screwed  an  olgect-glass  M,  which  can  also 
be  readily  removed,  and  others  adjusted  as  different  powers  are  required.  At 
F,  within  the  smaller  horizontal  tube,  the  prism  described  in  the  last  figure  is 
placed,  which,  receiving  the  rays  from  the  object  through  the  object-glass,  reflects 
them  to  the  eye-glass  at  H.  By  the  side  of  the  brass  pillar  is  a  square  bar  of 
copper  O  P,  which  is  firmly  fastened  to  the  pillar,  and  crosspiece  N,  at  the  bot- 
tom and  top.  Two  brass  sliding-collars  S  and  R,  are  capable  of  motion  up  and 
down  the  copper  bar,  by  means  of  two  toothed  axles  or  pinions,  the  heads  of 
which  are  seen  at  V  and  T. 

To  the  first  of  these  slides  S,  a  mirror  W,  is  attached,  possessing  motion  in 
all  directions  by  means  of  pivots,  and  having  on  one  side  a  plane  and  on  the 
other  a  convex  mirror.  The  slide  R  supports  a  table  X,  pierced  with  an  open- 
ing in  the  centre  immediately  under  M,  in  order  to  admit  the  light  reflected  up- 
wards from  the  mirror.  Over  this  opening  the  object  to  be  magnified  is  adjust- 
ed, placed  on  the  surface  of  a  slip  of  glass,  and  illumined  by  the  light  reflected 
from  the  mirror  below.  For  the  purpose  of  illumination,  either  the  diffuse  light 
of  day  or  lamplight  can  be  employed.  When  simple  reflection  produces  sufficient 
light,  the  plane  mirror  is  used,  but  if  a  stronger  illumination  is  needed  the  con- 
cave mirror  receives  the  light  and  concentrates  it  in  the  manner  of  .a  convex  lens. 
Beneath  the  opening  in  the  table,  a  plate  of  metal  is  so  adjusted  as  to  move 
horizontally,  perforated  with  apertures  of  different  sizes,  in  order  that  the  amount 
of  light,  admitted  through  the  opening  in  the  centre  of  the  table,  may  be  modified 
as  circumstances  require.  The  table  X,  is  composed  of  three  floors,  one  upon  the 
other,  two  being  capable  of  motion  in  directions  of  right  angles  to  each  other, 
while  the  third  and  lower  one  is  stationary.  Thus,  when  an  observer  is  looking 
through  the  instrument,  the  uppe/  floor  can  be  moved  to  the  right  and  left  by 
the  screw  Y,  and  this  floor,  together  with  the  second  immediately  below,  can  be 
unitedly  moved  backwards  and  forwards  by  a  screw  not  seen  in  the  plate. 

By  this  contrivance  an  object,  when  laid  upon  the  table,  is  capable  of  being 
moved  in  any  horizontal  direction,  so  that  every  part  of  it  can  be  successively 
brought  into  view.  The  table  can  be  raised  and  lowered,  in  the  manner  before 
mentioned,  by  the  screw  V,  and  the  object  is  thus  brought  to  that  position  before 


INTRODUCTORY    CHAPTER.  13 

the  object-glass  in  which  its  magnified  image  is  clearly  discerned.  In  order,  how- 
ever, to  effect  this  adjustment  with  the  greatest  nicety,  the  table  is  capable  of  a 
second  motion  upon  the  sliding  collar  R,  by  means  of  the  micrometer  screw  Z, 
which  elevates  and  depresses  the  table  through  minuter  portions  of  space  than 
the  pinion  V.  The  motion  of  the  sliding  tube  G,  by  the  action  of  the  pinion  K, 
is  employed  for  the  same  purpose,  and  also  for  increasing  and  diminishing  the 
magnifying  power  with  the  same  eye-piece. 

The  instrument  is  furnished  with  an  assortment  of  object-lenses  and  eye-glasses, 
which  can  be  used  either  singly  or  in  combination.  An  object  can  be  seen  with  per- 
fect distinctness  when  it  is  magnified  nearly  five  hundred  times,  and  superfi- 
cially 250,000,  but  when  the  magnifying  powers  employed  range  from  one  to 
four  thousand,  the  outlines  of  the  images  are  no  longer  well  preserved,  and  they 
become  somewhat  obscured. 

In  order  to  enable  the  observer  to  measure  the  size  of  minute  objects,  the  in- 
strument is  provided  with  a  scale  (Q)  ruled  upon  glass.  This  scale  is  about  the 
twenty-fifth  part  of  an  inch  in  length,  and  is  divided  accurately  by  the  point  of 
a  diamond  into  one  hundred  equal  parts.  Each  division,  therefore,  is  about 
^th  of  Ttroth  of  an' inch,  or  one-twenty-five  hundredth  of  an  inch  in  length. 
These  minute  divisions  are  clearly  discerned,  and  have  each  a  visible  length  even 
under  the  low  powers  of  the  microscope ;  and  by  laying  a  small  object,  as  a 
hair  for  instance,  across  this  scale,  its  dimensions  can  be  accurately  determined ; 
thus,  if  the  breadth  of  the  hair  occupies  twenty -five  divisions  of  the  scale,  its 
breadth  is  ^f f^th,  or  one-one  hundredth  of  an  inch,  and  so  for  any  other  thick- 
ness. If,  however,  the  object  to  be  magnified  cannot  be  laid  directly  upon 
the  scale,  its  dimensions  may  be  taken  by  means  of  the  camera  lucida,  an  opti- 
cal instrument  which  can  be  attached  at  pleasure  to  the  microscope.  By  its 
aid  the  observer  beholds  at  the  same  time,  and  in  the  same  direction,  the  magnified 
object  and  the  image  of  a  sheet  of  paper  placed  upon  the  table  before  him.  The 
magnified  object  lies  apparently  upon  the  paper  and  can  be  drawn  upon  the  sur- 
face of  the  latter  under  all  its  enlarged  dimensions.  The  object  may  then  be  re- 
moved, and  the  scale  placed  in  its  stead  beneath  the  microscope,  and  an  image  of 
its  magnified  divisions  also  drawn.  This  drawing  being  now  compared  with  that 
made  of  the  magnified  object,  the  dimensions  of  the  latter  are  readily  ascer- 
tained. Thus,  if  the  drawing  of  a  magnified  feather  of  a  butterfly's  wing  is  one 
inch  in  breadth,  and  the  length  of  the  drawing  of  ten  divisions  of  the  scale, 
equally  magnified,  is  also  one  inch,  then  the  natural  breadth  of  the  feather  is  ten 
times  2rVotn>  or  one-two  hundredth  and  fiftieth  part  of  an  inch. 

SOLAR  MICROSCOPE. — This  instrument  is  better  adapted  to  popular  illustra- 
tions, than  to  accurate  and  delicate  investigations ;  being  far  inferior  to  the 
compound  microscope  in  the  perfection  of  its  construction. 

The  essential  parts  of  a  solar  microscope  are  a  mirror,  a  condensing  lens,  and 
an  object-glass. 

The  lenses  are  placed  within  a  brass  tube,  the  larger  and  open  end  of  which 


14  VIEWS    OF    THE    MICROSCOPIC    WORLD. 

is  screwed  into  a  circular  aperture  made  in  a  thick  piece  of  wood,  and  to  the 
wood  on  the  opposite  side  a  mirror  is  attached  of  a  rectangular  shape.  When 
the  microscope  is  used,  the  mirror  is  thrust  through  an  opening  in  a  window- 
shutter,  and  the  piece  of  wood,  with  the  attached  tube  and  its  lenses,  firmly  fas- 
tened on  the  inside.  All  the  shutters  of  the  room  being  now  closed,  the  mirror 
is  so  adjusted  as  to  receive  the  direct  rays  of  the  sun  and  reflect  them  along  the 
tube,  where  they  are  received  by  the  condensing  lens,  which  concentrates  them 
upon  the  object,  placed  a  little  farther  from  the  object-glass  than  the  principal 
focus. 

The  object  being  thus  highly  illuminated,  the  bright  rays  that  proceed  from 
it  and  fall  upon  the  object-glass  converge  and  form  a  magnified  and  inverted 
image  upon  the  surface  of  a  large  screen,  placed  at  a  distance  at  the  opposite 
side  of  the  apartment. 

In  consequence  of  the  powerful  concentration  of  light  upon  the  object,  the 
image  may  be  distinctly  seen  by  a  number  of  spectators  in  various  parts  of  the 
room.  The  image  is  formed  in  the  manner  already  described  under  figure  2, 
where  B  L  in  this  case  would  be  the  distance  of  the  object  from  the  centre  of  the 
object-glass  D  E,  and  L  G  the  distance  of  the  screen.  Thus  if  B  L  was  one-tenth 
of  an  inch  in  length,  and  L  G  twenty  feet,  the  object  would  be  magnified  linearly 
2400  times,  and  superficially  5,760,000  times. 

In  this  form  of  the  solar  microscope,  transparent  objects  only  can  b§  viewed ; 
opaque  objects  may  also  be  magnified,  when  their  surfaces  are  rendered  intensely 
bright  by  the  aid  of  special  contrivances  for  concentrating  the  light  upon  them. 
In  place  of  the  solar  rays,  the  dazzling  light  caused  by  an  ignited  jet  of  hydro- 
gen and  oxygen  gases  playing  upon  carbonate  of  lime,  has  been  advantageously 
employed  for  this  microscope,  and  the  still  more  brilliant  light  produced  by  the 
galvanic  battery,  when  its  poles  are  tipped  with  charcoal  points. 


INFUSORIAL    ANIMALCULES.  15 


CHAPTER   I. 

INFUSORIAL    ANIMALCULES. 

"  Full  Nature  swarms  with  life ;  one  wondrous  mass 
Of  animals,  or  atoms  organized, 
Waiting  the  vital  breath  when  Parent-Heaven 
Shall  bid  His  spirit  blow.     The  hoary  fen, 
In  putrid  streams,  emits  the  living  cloud 
Of  pestilence.     Through  subterranean  cells, 
Where  searching  sunbeams  scarce  can  find  a  way, 
Earth  animated  heaves — and  where  the  pool 
Stands  mantled  o'er  with  green,  invisible, 
Amid  the  floating  verdure  millions  stray. 
Each  liquid  too,  whether  it  pierces,  soothes, 
Inflames,  refreshes  or  exalts  the  taste, 
With  various  forms  abounds.    Nor  is  the  stream 
Of  purest  crystal,  nor  the  lucid  air, 
Though  one  transparent  vacancy  it  seems, 
Void  of  their  unseen  people." — Thomson. 

THE  name  of  infusorial  animalcules  has  been  given  to  various  species  of 
minute  living  beings,  which  were  first  discovered  in  vegetable  infusions  ;  that  is,  in 
water  containing  vegetable  matter.  From  the  latter  circumstance  they  received 
the  appellation  infusorial,  and  in  consequence  of  their  being  exceedingly  small 
they  were  termed  animalcules  or  little  animals. 

It  was  supposed  by  the  earlier  naturalists,  that  the  animalcules,  whose  exist- 
ence was  thus  detected,  were  confined  to  certain  infusions ;  but  it  is  now  well 
ascertained  that  there  is  no  necessary  connexion  between  them  and  the  vegetable 
ingredients,  except  to  this  extent ;  that  the  latter,  under  favorable  circumstances, 
may  perhaps  facilitate  the  development  of  the  eggs  of  these  living  atoms,  and 
afford  a  proper  nourishment  for  the  animalcule,  through  all  the  stages  of  its 
existence. 

As  this  department  of  nature  became  more  thoroughly  and  widely  explored, 
new  species  of  animalcules  were  discovered,  and  the  general  term  of  infusorial 
animalcules,  has  therefore  been  so  enlarged  in  its  signification  as  to  embrace,  not 
only  that  class  of  minute  beings  that  are  found  in  vegetable  infusions,  but  all 
those  that  possess  the  same  marked  peculiarities  of  structure,  wherever  discovered. 
In  the  gushing  fount,  the  rippling  brook,  and  the  placid  waters  of  the  lake,  infu- 


16  VIEWS    OF    THE   MICROSCOPIC    WORLD. 

sorial  animalcules  exist  in  countless  numbers — often  swarming  to  such  an  extent, 
as  even  to  color  the  element  in  which  they  live.  One  species  tinges  the  water 
with  a  blood-red  hue,  another  causes  it  to  appear  of  an  intensely  vivid  green ; 
while  a  bright  orange  hue  indicates  the  presence  of  a  different  species.  They  are 
likewise  found  in  strong  acids,  and  in  the  fluids  contained  in  animal  bodies  and 
living  plants,  and  have  also  been  detected  alive  in  moist  earth,  sixty  feet  below 
the  surface  of  the  soil.  The  broad  rivers  are  their  home,  and  far  from  shore, 
upon  the  tropic  seas,  the  ocean  swarms,  for  leagues,  with  their  congregated 
myriads ;  and  as  the  bark  of  the  mariner  nightly  cuts  the  wave,  the  dazzling 
track  it  leaves  upon  the  waters,  and  the  fiery  spray  that  flashes  from  its  bows, 
tell  of  the  presence  of  life  enshrined  within  an  infinity  of  living  atoms.  Nor  is 
the  bed  of  the  ocean  without  its  minute  inhabitants  ;  for  the  mud  brought  up 
by  the  deep  sea-lead,  from  the  depth  of  sixteen  hundred  feet,  is  full  of  organic 
life.  There  is  also  every  reason  for  believing,  that  the  atmosphere  abounds  with 
the  eggs  of  animalcules,  as  it  does  with  the  seeds  of  minute  plants  ;  and  that 
these  germs,  being  inconceivably  light,  are  raised  by  evaporation,  and  borne 
about  by  the  winds  in  unseen  clouds ;  ready  to  burst  into  life  whenever  a  con- 
currence of  favorable  circumstances  facilitates  their  development.  Lifted  at  one 
time  to  the  loftiest  mountain  tops,  at  another  carried  down  to  the  lowest  dells 
and  deepest  caverns  ;  they  cross  seas,  sweep  over  continents,  and  interchange 
climes  and  seasons.  In  this  manner  are  these  invisible  forms  disseminated  over 
every  part  of  the  world  ;  for  wherever  investigations  have  been  prosecuted,  infu- 
sorial animalcules  have  been  discovered. 

Through  the  patient  and  persevering  labors  of  distinguished  naturalists,  no  less 
than  seven  hundred  and  eighty-six  different  species  of  animalcules  have  been  dis- 
tinctly recognised  and  delineated,  and  grouped  into  families  and  classes  ;  distin- 
guished from  each  other  by  their  forms,  manner  of  progression,  habits,  and 
modes  of  reproduction.  One  kind  are  beheld  dwelling  harmoniously  together 
within  a  delicate  transparent  shell,  which  in  one  case  assumes  a  spherical,  and  in 
others  a  quadrangular  form  ;  the  living  globes  with  all  their  inhabitants,  as  if 
actuated  by  a  single  will,  rolling  in  perfect  freedom  within  the  confines  of  a  drop 
of  water.  And  within  each  of  these  globes  smaller  globes  are  discerned,  enjoy- 
ing their  existence  equally  with  those  from  which  they  are  separated  by  the 
surrounding  crystalline  sphere.  Other  infusoria  possess  the  power  of  changing 
their  forms  at  will,  and  in  the  space  of  a  few  minutes  pass  through  a  variety  of 
curious  and  grotesque  shapes. 

Another  class  shoot  up  in  the  form  of  beautiful  shrubs,  crowned  with  bell- 
shaped  flowers,  whose  margins  are  encircled  with  a  fringe  of  slender  hairs  ;  but 
the  flower-cups  are  living  beings,  and  the  mimic  tree  is  instinct  with  vitality  in 
every  branch.  At  one  moment,  it  is  seen  spreading  outward  and  upward  from 
the  base,  with  all  its  living  flowers  in  full  expansion ;  and  at  the  next,  should 
danger  threaten,  every  shoot  suddenly  contracts,  and  the  whole  group  of  animal- 
cules shrink  down  in  spiral  coils,  into  the  smallest  compass.  The  great  variety 
of  form  possessed  by  these  interesting  objects,  can  only  be  fully  conceived  by  ex- 


INFUSORIAL    ANIMALCULES.  lY 

amining  those  works  in  which  they  are  accurately  delineated.  In  the  great  work 
of  Dr.  Ehrenberg,  who  has  devoted  his  life  to  the  study  of  animalcules,  they  are 
beheld  in  all  their  beautiful  and  singular  proportions.  This  splendid  volume,  of 
folio  size,  contains  sixty-four  plates,  filled  with  several  hundred  infusorial  shapes, 
drawn  and  colored  from  nature.  Some  resemble  globes,  trumpets,  stars,  boats, 
and  coins ;  others  assume  the  forms  of  eels  and  serpents  ;  and  many  appear  in 
the  shape  of  fruits,  necklaces,  pitchers,  wheels,  flasks,  cups,  funnels,  and  fans. 

But  the  minuteness  of  these  beings  is  no  less  surprising  than  the  diversity  of 
their  forms.  The  Monad,  the  smallest  of  all  known  living  creatures,  swarms  by 
myriads  in  a  drop  of  water ;  for  it  has  been  computed  that  within  this  small 
space,  no  less  than  Jive  hundred  millions  could  be  comprised  ;  and  this  calculation 
is  not  to  be  regarded  as  unworthy  of  confidence,  inasmuch  as  the  Monad  is  never 
found  to  attain  a  length  greater  than  the  twelve  thousandth  part  of  an  inch.  In 
a  cubic  inch  of  a  certain  kind  of  mould,  consisting  entirely  of  animalcules,  more 
than  forty-one  millions  of  distinct  beings  were  estimated  by  Ehrenberg  to  exist ; 
a  fact  which,  when  taken  in  connexion  with  others,  of  the  same  nature,  render  it 
highly  probable,  that  the  living  beings  of  the  microscopic  world  surpass  in  num- 
ber those  which  are  visible  to  the  naked  eye. 

STRUCTURE. — The  outer  covering  of  infusorial  animalcules  is  of  two  kinds; 
the  first  soft  and  yielding,  resembling  the  skin  of  the  leech  and  slug,  and  so  far 
capable  of  expansion  and  contraction  as  to  adapt  itself  to  the  state  of  the  ani- 
malcule whether  distended  or  not ;  the  second  presenting  the  appearance  of  a 
firm,  transparent  shell,  yet  possessing  a  flexibility  like  horn.  Those  animalcules 
that  are  protected  by  the  latter  integument  are  termed  loricated,  from  the  Latin 
word  lorica,  a  shell ;  while  the  name  illoricated  or  shelless,  is  assigned  to  those 
which  are  invested  with  the  softer  and  more  perishable  covering.  The  materials 
that  compose  the  shell  vary  in  different  species ;  in  many  instances  it  consists 
entirely  of  flint,  and  in  others  of  lime  united  with  oxide  of  iron ;  in  some  cases  it 
is  combustible  and  in  others  not.  In  several  kinds,  the  lorica,  in  the  form  of  a 
jar  or  cylinder,  entirely  surrounds  the  animalcule,  while  in  others  it  is  shaped  like 
a  shield,  and  protects  the  living  atom  to  which  it  belongs,  as  the  shell  of  the 
turtle  defends  its  sluggish  inhabitant  from  external  danger. 

When  the  loricated  infusoria  die,  their  shells  yet  remain,  uninjured  for  ages, 
and  in  several  parts  of  the  world  have  been  discovered  accumulated  in  such  vast 
quantities  as  to  form  extensive  deposits  of  marl,  lime,  and  flint,  of  which  we 
shall  speak  more  particularly  hereafter. 

It  was  formerly  believed,  that  the  smaller  species  of  animalcules  were  entirely 
destitute  of  external  organs  ;  but  such  improvements  have  now  been  made  in 
the  construction  of  microscopes,  and  the  organization  of  the  living  objects  has 
been  rendered  so  much  more  distinct,  from  the  practice  of  feeding  them  on  color- 
ed substances  before  examination,  that  this  supposition  has  been  shown  to  be 
entirely  unfounded,  even  in  the  case  of  monads. 

These  external  organs  vary  in  kind  in  different  animalcules,  but  the  one  which 

2 


18  VIEWS    OF   THE    MICROSCOPIC    WORLD. 

is  the  most  remarkable,  and  is  common  to  all  Infusoria,  is  a  slender  filament  like 
a  hair,  situated  near  the  mouth,  and  from  its  striking  resemblance  to  an  eye-lash 
is  known  by  the  name  of  cilium,  the  Latin  word  for  eye-lash. 

The  cilium  is  employed  by  the  animalcule  for  the  purpose  of  motion,  and  also 
for  that  of  procuring  food.  Using  this  member  as  an  oar,  the  creature  moves 
swiftly  through  the  water,  and  so  curious  is  the  action  of  this  propeller,  that  the 
verj  stroke  which  effects  a  progressive  motion,  causes  at  the  same  time  a  current  to 
set  towards  the  mouth  of  the  animalcule,  bearing  its  prey  and  food  within  its  reach. 

In  addition  to  the  offices  of  the  cilia*  just  described,  they  are  supposed  by  some 
naturalists  to  be  the  principal  instruments  for  respiration  to  the  Infusorial  world ; 
inasmuch  as  similar  appendages  are  found  encircling  the  gills  or  beard  of  the 
oyster  and  muscle,  and  other  animals  of  the  like  nature.  It  is  by  means  of  the 
gills  that  these  creatures  inhale  the  air  contained  in  the  water,  and  the  cilia  by 
causing  currents  to  flow  towards  these  organs,  furnish  a  continual  supply  of 
fresh  air.  According  to  Mantell,  "  recent  discoveries  have  shown  that  cilia  exist 
also  in  the  internal  organs  of  man  and  other  vertebrated  animals,  and  are  agents 
by  which  many  of  the  most  important  functions  of  the  animal  economy  are  per- 
formed." 

When  an  animalcule  is  examined,  this  delicate  member  easily  eludes  observa- 
tion, but  if  the  creature  is  placed  in  a  drop  of  water  colored  with  indigo  or  car- 
mine, the  little  whirls  and  currents  created  by  the  action  of  the  cilia  are  readily 
detected  under  the  microscope  ;  and  upon  the  evaporation  of  the  water  from  the 
glass  slide,  a  fine  streak  upon  the  surface  indicates  its  existence  and  position. 

These  slender  organs  are  variously  arranged  in  different  species  of  Infusoria. 
In  some  they  are  extended  in  rows  throughout  the  entire  length  of  the  animal- 
cule, and  in  others  are  distributed  over  the  whole  surface  of  the  body.  Fringes 
of  cilia  encircle  the  mouths  of  some,  while  in  many  kinds,  the  circles  of  cilia 
forming  into  bands,  surround  certain  projections  "issuing  from  the  upper  part 
of  the  body.  Numerous  species  are  furnished  with  only  two  of  these  filaments 
projecting  from  the  mouth,  and  nearly  equal  to  the  body  in  length.  The  base 
of  each  cilium  terminates  in  a  bulb,  and  when  the  organ  is  in  motion  its  point 
describes  a  circle,  while  the  globular  base  simply  rolls  round  upon  the  surface  to 
which  it  is  attached.  An  idea  may  be  gained  of  this  motion  by  holding  the 
arm  out  stiffly  and  swinging  it  round,  so  as  to  describe  a  circle  in  the  air  with 
the  point  of  a  finger ;  the  arm  then  corresponds  to  one  of  the  cilia,  and  the 
ball  of  the  shoulder-joint  to  the  bulb  upon  which  the  cilium  turns.  The  motion 
is  doubtless  performed  by  muscles,  and  Ehrenberg  considers  that  he  has  not  only 
discovered  their  existence  in  some  of  the  larger  Infusoria,  but  also  the  arrange- 
ment of  the  fibres  that  compose  them. 

The  bands  and  coronets  of  cilia,  which  encircle  certain  classes  of  animalcules, 
present  when  in  motion  a  singular  appearance.  Though  each  organ  is  stationary 
and  revolves  only  around  its  bulb,  yet  the  combined  action  of  the  circular  rows 

*  Cilia,  the  plural  of  cilium. 


INFUSORIAL    ANIMALCULES.  19 

is  such,  that  they  appear  to  revolve  together  like  a  wheel  upon  its  axle,  and  so 
complete  is  the  illusion  that  the  name  of  wheel-animalcules,  or  Rotatoria,  is  given 
to  those  which  possess  this  peculiarity. 

Besides  these  organs,  stiff  hairs  or  bristles  are  found  upon  animalcules,  which, 
unlike  the  cilia,  are  devoid  of  rotation,  but  serve  as  supports  to  the  body,  and 
also  aid  these  living  atoms  in  climbing.  Animalcules  are  also  found  with  hook- 
like  projections  extending  from  the  under  side  of  the  body,  which  are  capable  of 
motion  to  some  extent,  but  do  not  possess  the  peculiar  movement  of  the  cilia. 
Many  Infusoria  are  also  endowed  with  another  kind  of  member,  that  more  com- 
pletely subserves  the  purpose  of  motion,  and  which  they  have  the  power  of  pro- 
truding or  withdrawing  at  pleasure,  as  the  snail  extends  and  retracts  its  horns. 
These  organs  are  soft,  and  by  some  species  can  be  thrust  out  from  every  part  of 
the  body;  while  in  others  that  are  partially  covered  by  a  shell,  they  are  confined 
to  the  uncovered  portions. 

The  power  of  extension  possessed  by  Infusoria  over  these  organs  is  much 
greater,  in  proportion  to  their  size,  than  in  the  case  of  snails  and  animals  of  a 
similar  nature. 

In  those  Infusoria  that  are  gifted  with  the  highest  organization,  as  the  wheel- 
bearing  animalcules,  there  appears  to  be  a  member  resembling  a  claw,  by  means 
of  which  they  attach  themselves  firmly  to  any  object  within  their  grasp.  The 
claw  is  appended  to  an  extended  portion  of  the  body,  resembling  a  foot. 

CLASSIFICATION. — Dr.  Ehrenberg,  to  whom  we  are  more  indebted  than  to  any 
other  observer,  for  our  knowledge  of  Infusoria,  divides  this  living  world  into  two 
great  classes,  distinguished  from  each  other  by  their  structure :  viz.,  the  Poly- 
gastrica*  or  many-stomached  animalcule,  and  the  Rotatoriaf  or  wheel-animalcule. 

POLYGASTRICA. —  If  an  animalcule  of  this  class  is  viewed  by  the  microscope,  a 
number  of  round  spots  within  its  body  will  be  readily  detected,  which  are  often 
quite  large  compared  with  the  size  of  the  living  atom.  These  spots  are  so  many 
stomachs,  connected  together  by  a  single  tube,  and  forming  the  digestive  appa- 
ratus of  the  creature.  If  the  water  around  the  animalcule  is  clear,  the  stomachs 
will  appear  more  transparent  than  the  rest  of  the  body  ;  but  if  it  is  tinted  with 
sap-green  or  carmine  (which  substances  are  usually  employed)  they  will  be  seen 
more  distinctly  ;  for  the  animalcule  readily  imbibes  the  colored  fluid,  and  the 
stomachs  from  their  transparency  then  appear  of  the  same  hue  as  the  liquid ; — 
while  the  tint  of  the  more  solid  portions  of  the  body  remains  unchanged.  The 
number  of  stomachs  varies  in  different  species  from  four  to  upwards  of  two  hundred. 

In  the  annexed  cut  a  highly  magnified  view  of  a  bell-shaped  animalcule  is 
presented,  in  which  the  stomachs  and  coronets  of  cilia  are  distinctly  exhibited. 

None  of  this  class  of  infusoria  are  more  than  the  twelfth  of  an  inch  long,  and 
the  smallest  species,  when  full  grown,  do  not  exceed  in  extent  the  thirty-six  thous 

*  From  the  Greek  polus,  many,  and  gaster,  a  stomach        f  From  the  Latin  rota,  a  wheel. 


20 


VIEWS    OF    THE    MICROSCOPIC    WORLD. 


andth  part  of  an  inch.  Uniting,  however,  in  infinite 
multitudes,  the  more  minute  kinds  form  various  colored 
'masses,  several  feet  in  length.  The  young  of  many 
species  are  doubtless  too  minute  to  be  visible  even  un- 
der the  highest  powers  of  the  microscope. 

Most  of  the  Poly  gas  trica  reside  in  fresh  water,  but 
many  species  inhabit  the  ocean.  They  are  likewise 
found  living  in  moist  earth,  in  peat  bogs,  in  animal 
fluids,  and  in  water  in  which  astringent  substances,  such 
as  bark,  have  been  infused.  It  has  even  been  supposed 
that  from  their  extreme  lightness  some  species  may 
dwell  in  the  moisture  of  the  atmosphere,  being  driven 
about  in  unseen  countless  numbers,  at  the  sport  of  every 

A  BELL-SHAPBTD  ANIMALCULE,   wind.     One-half  of  the  kinds  composing  this  class  are 
c.  cilia,   s.  The  stomachs,     loricated,   the   other  half  illoricated;    and   from   the 
former   are    derived  those  vast  collections  of  minute  shells,  which  often  con- 
stitute for  leagues  a  large  portion  of  the  surface  of  the  earth ;  the  enduring  me- 
morials of  innumerable  beings  which  perished  centuries  ago. 

ROTATORIA. — The  second  class  of  Infusoria  have  received  the  appellation  of 
Rotatoria,  as  has  already  been  stated,  from  the  circumstance  that  the  circles  of 
cilia  which  surround  the  upper  part  of  the  body  of  the  animal  appear  when  in 
motion  to  revolve  like  a  wheel.  The  cilia  are  found  upon  no  other  portion  of 


Figure  7. 


their  body,  while  in  the  Poly- 
gastrica  they  are  distributed 
over  the  entire  surface.  In  some 
species  the  crowns  of  cilia  con- 
sist of  a  single  set,  and  in  oth- 
ers several  circular  rows  of  dif- 
ferent forms  are  distinctly  no- 
ticed. This  class  of  Infusoria  is 
endowed  with  a  highly  perfect- 
ed organization,  and  on  account 
of  their  comparatively  large 
size,  some  of  them  attaining  a 
length  of  one-thirtieth  of  an 
inch,  both  their  external  and 
internal  structure  are  well  re- 
vealed by  the  microscope.  The 
Rotatoria  possess  a  single  sto- 
mach, and  many  kinds  are 
furnished  with  jaws  and  teeth, 

aa.  The  Cilia,    bb.  The  Eyes.    c.  The  Jaws  and  Teeth.  wm'ch      toget}ier      with      other 

parts  will  be  particularly   described   hereafter,  when  treating  of  individual  ani- 


INFUSORIAL    ANIMALCULES.  21 

malcules  belonging  to  this  class.  The  preceding  cut,  Fig.  7,  is,  however,  given  at 
present  for  the  sake  of  illustration. .  It  displays  the  upper  part  of  a  common  wheel- 
animalcule,  with  the  circles  of  cilia,  jaws,  teeth,  and  eyes,  all  highly  magnified. 

The  Eotatoria  reside  chiefly  in  water,  but  are  frequently  found  in  moist  earth, 
and  some  species  have  been  detected  dwelling  in  the  cells  of  mosses  and  sea-weed. 

EYES. — By  the  aid  of  the  microscope  as  now  perfected,  naturalists  have  dis- 
covered eyes  throughout  the  entire  class  of  Rotatorial  animalcules ;  and  likewise 
in  many  kinds  of  the  Poly  gas  trica.  A  fact  that  indicates  the  existence  of  a  ner- 
vous system  in  these  living  atoms.  The  eye  of  larger  animals  is  known  to  be  an 
organ  exceedingly  complicated  in  its  structure,  and  replete  with  the  most  beauti- 
ful contrivances  to  insure  perfect  vision.  There  is  every  reason  for  believing  that 
the  same  is  true  of  the  eyes  of  animalcules ;  and  if  this  is  so,  how  can  we  suffi- 
ciently admire  the  wondrous  perfection  and  consummate  skill  which  the  Creator 
has  deigned  to  bestow  upon  some  of  the  least  of  his  revealed  works ;  and  above 
all,  the  unwearied  benevolence  displayed  in  every  manifestation  of  His  infinite 
power !  Beginning  with  the  Monad,  and  examining  the  Infusorial  world  from 
the  smallest  upward,  the  Microglena  is  the  first  which  is  found  to  possess  a  visual 
organ.  This  living  point  is  sometimes  less  than  the  two-thousandth  part  of  an 
inch  in  size,  yet  it  is  gifted  with  a  beautiful  eye  of  a  crimson  hue,  wherein  the 
scenes  of  its  own  little  world  are  doubtless  as  faithfully  mirrored,  as  are  within 
our  eyes  the  wide  range  of  objects  upon  which  we  gaze.  The  Polygastrica  have 
usually  but  one  eye,  and  are  only  in  a  few  cases  possessed  of  two.  The  eyes  of 
the  Rotatoria  are  generally  red,  and  most  of  the  animalcules  belonging  to  this 
class  have  two  of  these  organs.  In  some  three  are  perceived ;  while  one  kind 
especially  has  the  benefit  of  seven  or  eight  on  each  side  of  the  head.  A  diver- 
sity exists  in  the  arrangement  of  the  eyes ;  in  many  instances  they  are  placed  in 
a  line,  side  by  side,  in  others  they  form  a  triangle.  In  some  animalcules  they 
are  arranged  in  a  circle,  and  in  two  species  they  unite  in  clusters  on  each  side  of 
the  head. 

REPRODUCTION. — Animalcules  multiply  in  several  ways.  First,  they  proceed 
from  eggs.  Secondly,  they  are  brought  forth  alive.  Thirdly,  they  increase  by 
the  growth  of  buds  issuing  from  the  body  of  the  parent ;  the  buds  sprouting  out 
and  becoming  themselves  perfectly  organized  animalcules.  Lastly,  they  are 
propagated  by  self-division,  the  body  of  an  animalcule  separating  into  two  or 
more  individual  beings. 

The  same  animalcule  is  not  always  confined  to  a  single  mode  of  reproduction, 
but  its  countless  offspring  may  come  into  existence  by  one  or  more  of  the  ways 
just  detailed  ;  one  part  being  produced  by  self-division,  another  from  eggs,  and 
the  remainder  originating  in  buds.  This  circumstance  accounts  for  the  amazing 
fecundity  of  the  Infusoria,  which  almost  surpasses  belief;  even  when  limited  to 
one  method  of  increase.  The  Rotatorial  animalcules  are  propagated  from  eggs 
alone,  and  but  a  few  of  these  are  deposited  at  a  time  ;  yet  so  quickly  are  the 


22  VIEWS    OF    THE    MICROSCOPIC    WORLD. 

young  matured,  that  from  a  single  animalcule  millions  will  proceed  in  the  course 
of  a  few  "days.  Dr.  Ehrenberg  kept  one  of  this  class  of  Infusoria  for  eighteen 
days  in  a  separate  vessel  of  water ;  during  this  interval  it  lai'd  four  eggs  a  day, 
and,  the  young,  when  two  days  old,  laid  the  same  number  ;  so  that,  continuing 
to  multiply  at  this  rate,  it  was  found  that  under  favorable  circumstances,  the  off- 
spring of  a  single  creature  would  amount,  in  the  course  of  ten  days,  to  one 
million  ;  in  eleven,  to  four  millions  ;  and  in  twelve  days,  to  sixteen  millions. 
This  is  the  greatest  increase  that  has  actually  been  determined  by  experiment. 
In  the  other  class  of  Infusoria,  the  Polygastrica,  the  fecundity  is  much  greater, 
inasmuch  as  they  are  endowed  with  more  varied  powers  of  reproduction.  A 
single  animalcule  belonging  to  one  of  the  larger  kinds  is  known  to  separate  into 
eight,  in  the  course  of  a  day,  by  self-division  ;  so  that,  multiplying  at  this  rate 
for  the  space  of  ten  days,  it  would  increase  to  more  than  one  hundred  and  fifty 
millions  individuals.  It  likewise  propagates  from  eggs,  which  are  seen  in  clusters 
like  the  spawn  of  fishes  ;  and  also  by  buds,  that  sprout  from  the  sides  of  its  body. 
When  all  these  facts  are  taken  into  view,  it  is  evident,  that  the  vast  number  of 
living  beings,  which  in  a  few  days  spring  from  a  creature  as  prolific  as  this,  is 
utterly  beyond  our  powers  of  appreciation.  It  has  been  affirmed  by  naturalists, 
that  such  is  the  amazing  fecundity  of  the  box-chain  animalcule  (Gallionella), 
that  in  twenty-four  hours  a  single  individual  will  increase  to  the  number  of  one 
hundred  and  forty  million  millions,  (140,000,000,000,000.) 

LIFE  AND  RESUSCITATION. — Infusorial  animalcules  live  but  for  a  short  period, 
for  although  the  duration  of  their  life  varies  in  different  kinds,  it  extends  only 
from  a  few  hours  to  several  weeks.  Wheel  animalcules  have  been  seen  in  the 
enjoyment  of  their  existence  twenty-three  days  after  their  birth.  The  death  of 
Infusoria  is  usually  sudden,  and  in  the  larger  species  is  attended  with  spasms. 
The  soft  parts  rapidly  decompose  after  death,  and  all  the  curious  and  elaborate 
organs  of  these  singular  beings  entirely  vanish  ;  nothing  appearing  to  remain 
except  the  transparent  flinty  shells  in  which  many  kinds  of  the  Infusoria  are  en- 
cased. But  in  numerous  instances,  this  death  is  but  apparent ;  the  decay  of  the 
body  does  not  take  place,  and  in  the  minute  speck,  that  lies  before  us  like  an 
atom  of  inanimate  dust,  the  mysterious  principle  of  life  is  still  in  existence.  The 
creature  may  remain  motionless  for  months,  and  even  years  ;  but  when  it  is  again 
subjected  to  influences  favorable  to  its  resuscitation,  it  awakens  from  its  torpor, 
and  life,  with  all  its  former  energies,  is  once  more  fully  displayed. 

This  surprising  phenomenon  is  supported  by  undoubted  proof.  When  the 
water  containing  a  wheel-animalcule  evaporates,  the  creature  apparently  expires, 
becomes  dry  and  hard,  and  may  be  preserved  in  this  state  for  years,  if  buried  in 
sand.  When  placed  in  water  in  this  condition,  it  will  revive  in  a  few  minutes,  and 
soon  swim  about  with  its  wonted  activity.  In  1701  Leuwenhoeck  observed  this 
fact  in  wheel  animalcules,  and  revived  some  specimens  after  keeping  them  dry  for 
twenty-one  months.  Baker  obtained  the  same  result  after  a  longer  time,  and 
Prof.  Owen  was  present  at  the  resuscitation  of  an  animalcule  after  it  had  lain 


INFUSORIAL    ANIMALCULES.  23 

dormant  in  dry  sand  for  four  yeats.  Nor  is  this  all ;  for  such  is  the  tenacity 
of  life  in  these  minute  beings,  that  the  same  animalcule  may  repeatedly  pass 
through  these  phases  of  existence  before  it  really  expires.  Mantell  remarks  that 
some  wheel  animals  were  alternately  dried  and  rendered  torpid,  and  then  again 
revived  twelve  times,  and  at  each  resuscitation  were  as  active  as  at  first. 

The  eleventh  revival  was  witnessed  by  Spallanzani ;  and  he  leads  us  to  infer, 
that  upon  moistening  a  portion  of  sand  containing  wheel-animalcules  for  the 
fifteenth  time,  many  of  them  once  more  awoke  from  their  stupor ;  but  this  was 
the  last  effort  of  vitality,  for  upon  being  dried  and  moistened  again,  no  resuscita- 
tion occurred.  The  wonderful  legend  of  the  Seven  Sleepers  is  here  more  than 
realized  ;  and  in  the  Infusorial  world  the  romantic  fiction  of  Rip  Van  Winkle 
becomes  a  sober  statement  of  fact.  Thus  it  is  that  Fancy  in  her  wildest  flights 
seldom  sweeps  beyond  the  circle  of  truth. 

It  is  the  opinion  of  Dr.  Ehrenberg,  in  regard  to  this  subject,  that  if  the  ani- 
malcule is  entirely  dried  up  and  its  natural  heat  lost,  life  is  extinguished,  but  if 
this  is  not  the  case  the  creature  will  remain  in  a  torpid  and  motionless  state, 
capable  of  being  revived ;  its  body  wasting  away  to  an  extent  equal  to  the 
amount  of  nourishment  necessary  for  the  support  of  its  life, 

INFLUENCE  OF  TEMPERATURE. — Infusorial  animalcules  are  capable  of  existing 
throughout  a  great  range  of  temperature,  but  eventually  perish  under  extreme  de- 
grees of  heat  and  cold.  If  water  filled  with  Poly  gastric  Infusoria  is  gradually  raised 
to  a  temperature  of  125°  Fah.,  the  creatures  still  live  ;  and  Dr.  Ehrenberg  re- 
marks that  in  one  instance  several  animalcules  of  a  certain  kind  continued  alive 
at  the  temperature  of  200°  Fah.  If  the  increase  of  heat  is  sudden,  they  perish 
at  140°  Fah.,  although  the  temperature  is  maintained  for  only  half  a  minute. 
Some  kinds,  however,  are  extremely  sensitive,  and  are  unable  to  endure  an  or- 
dinary degree  of  warmth.  This  is  the  case  with  the  Bell-flower  animalcule, 
which  dies  under  examination  in  a  hot  room.  Most  of  the  Polygastrica  retain  their 
vitality  at  temperatures  considerably  below  the  freezing  point;  but  when  the  mer- 
cury descends  as  far  as  7°  or  8°  Fah.,  many  species  can  no  longer  exist.  One  kind 
of  the  Bell-flower  animalcule  still  lives  after  being  exposed  to  a  temperature  of 
8°  Fah.,  and  the  ice  then  gradually  thawed  in  which  it  was  frozen ;  but  not  more 
than  one  individual  in  a  hundred  can  survive  this  ordeal.  The  Rofcatorial  ani- 
malcules are  more  susceptible,  and  perish  when  the  cold  is  less  severe. 

During  the  Antarctic  expedition  under  Capt.  James  Ross,  animalcules  were 
found  existing  in  great  abundance  in  those  inclement  regions.  In  the  sediment 
obtained  from  melted  ice,  floating  in  round  masses,  in  the  latitude  of  70°,  more 
than  fifty  species  of  loricated  Infusoria  were  discovered  alive,  notwithstanding  the 
extreme  cold  to  which  they  had  been  exposed.  According  to  Dr.  Ehrenberg, 
when  a  layer  of  clear  ice  containing  animalcules  is  examined  under  a  low  tem- 
perature by  the  microscope,  each  animalcule  or  group  will  be  seen  surrounded 
by  a  very  small  portion  of  water,  which  he  supposes  is  prevented  from  freezing 
by  the  natural  heat  of  their  bodies ;  and  he  likewise  believes  that  death  inevita- 


24  VIEWS    OF    THE    MICROSCOPIC    WORLD. 

bly  ensues  whenever  the  cold  is  sufficiently  intense  to  congeal  this  enclosing  film 
of  water. 

AIR. — Air  is  as  necessary  to  existence  of  Infusoria  as  to  any  other  class  of 
animated  nature  ;  for  when  they  are  denied  access  to  the  atmosphere,  and  are 
thus  prevented  from  receiving  constant  supplies  of  pure  air,  life  becomes  extinct 
within  a  short  time.  If  oil  is  poured  upon  the  water  containing  animalcules, 
and  the  surface  of  the  fluid  is  entirely  covered  with  the  oil,  the  air  is  necessarily 
excluded  and  the  creatures  speedily  die.  Or  should  the  naturalist  fill  a  phial 
with  water  in  which  animalcules  reside,  and  leave  it  corked  tightly  for  any  length 
of  time,  he  will  have  the  mortification  of  finding,  on  examination,  that  the  fluid, 
once  so  full  of  life  and  activity,  has  become  entirely  inert,  and  that  millions  of 
existences  have  passed  away.  The  fact  that  air  is  necessary  to  the  existence  of 
Infusoria  has  been  particularly  noticed  in  regard  to  the  larger  kinds  of  wheel- 
animals  ;  for  when  experiments  have  been  made  by  placing  these  creatures  under 
the  receiver  of  an  air-pump,  they  have  always  ceased  to  live  soon  after  the  air 
has  been  withdrawn  from  the  vessel  in  which  they  were  contained. 

Dr.  Ehrenberg  affirms,  that  if  animalcules  are  placed  in  nitrogen  gas  they 
exist  for  a  longer  time  than  if  they  are  immersed  in  carbonic  acid  or  hydrogen 
gas.  In  the  fumes  of  sulphur  they  quickly  perish. 

POISONS. — The  most  powerful  poisons,  which  mingle  simply  in  a  mechanical 
manner  with  water,  like  earth,  do  not  effect  the  lives  of  animalcules  placed  in 
the  mixture  ;  but  those  which  unite  chemically,  and  are  dissolved  in  the  fluid, 
soon  deprive  them  of  their  existence.  One  kind  of  Infusoria  has  been  known  to 
live  so  long  in  water  with  which  calomel  and  corrosive  sublimate  had  been  mixed, 
that  it  was  doubtful  whether  their  death  was  to  be  attributed  to  the  effect  of 
these  ingredients  or  not. 

Many  species  of  animalcules  can  adapt  themselves  to  a  gradual  change  in  the 
nature  of  the  element  in  which  they  live,  but  a  sudden  transition  kills  them. 
For  instance,  similar  kinds  are  found  at  the  heads  of  rivers  where  the  water  is 
fresh,  and  at  their  mouths,  where  the  streams  mingle  with  the  briny  ocean. 

If  sea-water,  abounding  with  marine  animalcules,  is  mixed  by  slow  degrees 
with  the  fluid  in  which  fresh-water  species  reside,  the  latter  survive  ;  but  if  the 
mixture  is  suddenly  made,  they  perish  immediately. 

PHOSPHORESCENCE  OF  THE  SEA. — Various  opinions  have  at  times  been  enter- 
tained in  respect  to  the  cause  of  this  beautiful  phenomenon ;  but  it  is  now  cor- 
rectly attributed  chiefly  to  the  presence  of  animalcules,  which  crowd  the  waters 
in  vast  multitudes.  This  appearance,  although  confined  to  no  particular 
part  of  the  ocean,  attains  its  greatest  splendor  in  the  tropical  climes,  where  the 
spectacle  is  often  exceedingly  grand  and  beautiful. 

This  brilliant  phenomenon  is  thus  graphically  described  by  Darwin  in  his 
"  Voyage  of  a  Naturalist "  : — "  While  sailing  a  little  south  of  the  River  La  Plata, 


INFUSORIAL    ANIMALCULES.      .  25 

on  one  very  dark  night,  the  sea  presented  a  wonderful  and  most  beautiful  spec- 
tacle. There  was  a  fresh  breeze,  and  every  part  of  the  surface,  which,  during 
the  day,  is  seen  as  foam,  now  glowed  with  a  pale  light.  The  vessel  drove  before 
her  bows  two  billows  of  liquid  phosphorus,  and  in  her  wake  she  was  followed  by 
a  milky  train.  As  far  as  the  eye  reached,  the  crest  of  every  wave  was  bright, 
and  the  sky  above  the  horizon,  from  the  reflected  glare  of  these  livid  flames,  was 
not  so  utterly  obscure  as  over  the  vault  of  the  heavens.  Near  the  mouth  of  the 
Plata  some  circular  and  oval  patches,  from  two  to  four  yards  in  diameter,  shone 
with  a  steady  but  pale  light,  while  the  surrounding  water  only  gave  out  a  few 
sparks.  The  appearance  resembled  the  reflection  of  the  moon,  or  some  luminous 
body,  for  the  edges  were  sinuous  from  the  undulations  of  the  surface.  The  ship, 
which  drew  thirteen  feet  of  water,  passed  over  without  disturbing  these  patches ; 
we  must  therefore  suppose  that  some  of  the  luminous  marine  animals  were  con- 
gregated together  at  a  greater  depth  than  the  bottom  of  the  vessel,  or  thirteen 
feet  beneath  the  surface  of  the  sea." 

The  same  phenomenon  is  thus  depicted  in  the  glowing  language  of  Colton : — 
"  We  had  last  night  a  splendid  exhibition  of  aquatic  fire-works.  The  night  was 
perfectly  dark,  and  the  sea  smooth,  and  you  might  see  a  thousand  living  rockets 
shooting  in  all  directions  from  our  ship,  and  running  through  countless  configura- 
tions, return  to  her,  leaving  their  track  still  bright  with  unextinguishable  flame. 
Then  they  would  start  again,  whirling  through  every  possible  gyration,  till  the 
whole  ocean  around  seemed  medallioned  with  fire.  We  had  run  into  an  im- 
mense shoal  of  porpoises  and  small  fish ;  the  sea  being  filled  at  the  same  time 
with  animalcule,  which  emit  a  bright  phosphoric  light  when  the  water  is  agi- 
tated. The  chase  of  the  porpoises  after  these  small  fish  created  the  beautiful 
phenomenon  described.  The  light  was  so  strong  that  you  could  see  the  fish 
with  the  utmost  distinctness.  They  lit  their  own  path  like  a  sky-rocket  in  a  dark 
night ;  and  our  ship  left  the  track  of  its  keel  in  the  wave  for  half  a  mile.  I  have 
witnessed  the  illumination  of  St.  Peter's,  and  .the  castle  of  Michael  Angelo,  at 
Rome,  and  heard  the  shout  of  the  vast  multitudes  as  the  splendors  broke  over 
the  dark  cope  of  night,  but  no  pyrotechnic  displays  ever  got  up  by  human  skill, 
could  rival  the  exhibitions  of  nature  around  our  ship."  That  the  cause  of  this 
brilliant  phenomenon  is  correctly  assigned  to  marine  animals  has  been  proved 
by  the  examination  of  the  luminous  water,  for  if  it  is  placed  in  a  tumbler  and 
agitated,  they  immediately  emit  light  in  momentary  sparks.  Some  of  these  crea- 
tures are  of  considerable  dimensions  and  others  barely  visible,  but  a  great  pro- 
portion are  entirely  microscopic,  and  require  the  aid  of  powerful  instruments  in 
order  to  perceive  them  and  investigate  their  forms  and  nature. 

The  various  species  of  Infusoria  which  illumine  the  ocean,  are  extremely  small 
in  size ;  the  largest  do  not  exceed  one-hundredth  of  an  inch  in  extent,  while  the 
least,  hardly  attain  the  length  of  one-twelve  hundredths  of  an  inch.  The  phos- 
phoric light  emitted  by  these  creatures,  is  regarded  by  naturalists  as  the  effect 
of  a  vital  action  ;  it  appears  as  a  single  spark  like  that  of  the  firefly,  and  can  be 
repeated  in  a  similar  manner  at  short  intervals. 


26  VIEWS    OF    THE    MICROSCOPIC    WORLD. 

COLORED  TRACTS  OF  THE  OCEAN. — It  has  been  noticed  by  navigators  in  all 
parts  of  the  sea,  that  extensive  tracts  of  water  are  not  unfrequently  discolored  at  a 
great  distance  from  land.  This  change  in  the  hue  of  the  waves  is  caused  by  the 
presence  of  minute  marine  animals  and  Infusoria,  which  impart  their  own  tint  to 
the  waters  in  which  they  abound,  the  far  greater  part  being  too  small  to  be  ob- 
served by  the  naked  eye.  Nearly  one-fourth  of  the  Greenland  sea,  comprising  an 
area  of  more  than  twenty  thousand  square  miles,  is  of  a  deep  olive  green  hue. 
This  coloring  matter  was  discovered .  by  Mr.  Scoresby  to  consist  of  animalcules, 
which  crowded  the  water  in  infinite  numbers.  On  an  average,  sixty -four  animal- 
cules of  one  kind  were  found  in  every  cubic  inch  of  water  submitted  to  examina- 
tion, and,  on  the  supposition  that  they  were  equally  numerous  throughout  the 
body  of  colored  water,  Mr.  Scoresby  computed,  that  a  surface  of  two  square  miles 
and  fifteen  hundred  feet  deep,  contained  no  less  than  twenty-three  thousand 
millions  of  millions  of  animalcules  belonging  to  one  species.  And  in  order  to 
form  a  more  definite  idea  of  this  vast  multitude,  he  remarks,  that  the  number 
of  years  required  for  eighty  thousand  persons  to  count  them,  would  be  equal  to 
the  period  that  has  now  elapsed  since  the  creation  of  the  world. 

This  green  sea  is  described  as  the  Polar  pasture  ground,  the  animalcules 
affording  an  exhaustless  supply  of  sustenance  to  creatures  less  minute,  and  these 
likewise  becoming  the  food  of  larger  species,  which  in  their  turn  are  devoured  by 
others  of  greater  size.  And  thus  the  series  continues  to  increase  until  the  waters 
are  crowded  with  numerous  forms  and  types  of  animal  life,  the  prey  of  the  mighty 
monsters  of  the  deep,  which  in  vast  numbers  resort  to  these  prolific  seas. 

On  the  east  coast  of  Greenland  Mr.  Scoresby  also  met  with  broad  patches  and 
bands  of  water  of  a  yellowish-green  color,  as  if  sulphur  had  been  strewn  upon 
the  waves ;  and  upon  examining  it  with  a  microscope  it  was  found  swarming 
with  animalcules.  Most  of  them  were  of  a  globular  form  and  of  a  lemon  color, 
and  seemed  to  be  possessed  of  little  activity,  but  the  rest  were  in  constant  mo- 
tion. So  small  were  these  creatures  that  the  largest  did  not  exceed  the  two- 
thousandth  of  an  inch  in  length,  and  many  of  them  were  but  half  this  size.  A 
single  drop  of  the  water,  and  that  not  the  most  discolored,  was  found  to  contain 
more  than  twenty-six  thousand  animalcules.  The  glass  upon  which  the  drop 
was  placed  for  examination  was  ruled  into  small  squares  of  equal  size.  The  drop, 
when  magnified  linearly  one  hundred  and  sixty-eight  times,  covered  five  hundred 
and  twenty-nine  of  these  squares  ;  and  in  every  square,  on  an  average,  fifty  ani- 
malcules were  found ;  which  made  an  aggregate  of  twenty-six  thousand  four 
hundred  and  fifty.  Mr.  Scoresby  computed,  that  in  a  tumbler  of  water  one  hun- 
dred and  fifty  millions  of  these  animalcules  would  find  ample  room,  and  regard- 
ing each  as  one-four-thousandth  of  an  inch  long,  a  row  of  half  a  million  placed 
closely  side  by  side,  would  form  a  line  only  ten  feet  and  five  inches  in  extent. 
Oft'  the  coast  of  Chili,  at  the  distance  of  fifty  miles  from  shore,  Darwin  passed 
in  the  ship  Beagle  through  wide  bands  of  turbid  water;  a  single  tract  in  one 
case  comprising  an  area  of  several  square  miles.  When  viewed  at  a  distance, 
the  waves  appeared  red,  but  under  the  shade  of  the  vessel,  of  a  deep  chocolate 


INFUSORIAL    ANIMALCULES.  27 

color,  and  the  line  of  division  between  the  red  and  blue  water  was  clearly 
defined.  Upon  close  examination  in  a  glass,  the  water  assumed  a  pale  red  tint, 
and  when  viewed  by  the  microscope  was  found  crowded  with  animalcules  one- 
thousandth  of  an  inch  long,  of  an  oval  shape,  and  encircled  at  the  middle  with 
a  ring  of  cilia.  They  were  beheld  darting  about  in  all  directions  and  exploding, 
their  bodies  bursting  to  pieces  in  a  few  seconds  after  their  rapid  motions  had 
ceased.  A  stratum  of  red  water,  twenty-four  miles  long  and  seven  broad,  is 
mentioned  by  Dr.  -Pceppig,  as  occurring  near  Cape  Pilares.  When  beheld  from 
the  mast-head  it  appeared  of  a  dark  red  hue,  but  as  the  vessel  advanced  on  her 
course  it  changed  into  a  brilliant  purple,  while  a  rosy  tint  illumined  the  track 
of  the  keel.  This  water  was  perfectly  transparent,  but  small  red  specks  could 
be  perceived  moving  through  it  in  spiral  lines. 

Having  thus  briefly  discussed  the  nature,  structure,  and  habits  of  Infusoria, 
we  will  now  proceed  to  describe,  particularly,  some  of  the  more  interesting 
species. 

POLYGASTRIC  ANIMALCULES. 

MONADS. — These  are  the  smallest  of  all  living  creatures,  which  the  wonderful 
power  of  the  microscope  has  revealed  to  us.  So  minute  are  they,  that  they  must  be 
magnified  linearly  300  times  in  order  to  be  seen  at  all,  and  500  times  if  we  wish  to 
observe  them  accurately.  They  appear  as  transparent  globular  or  oval  bodies,  mov- 
ing rapidly  about  in  all  directions.  Some  are  of  a  red  hue,  others  green,  many  yel- 
low, but  the  greater  part  are  colorless.  All  are  possessed  of  one  or  more  organs 
of  motion.  Many  are  destitute  of  eyes,  but  in  others  a  bright  red  eye  has  been 
detected.  The  individuals  of  this  family  of  Infusoria  vary  in  size,  from  one- 
twenty-four-thousandth  of  an  inch  in  length,  to  one-forty-thousandth  of  an  inch. 

TWILIGHT  MONAD. — In  figure  8,  is  shown  a  group  of  twilight  monads,  F1s- 8- 
in  which  each  creature,  although  exhibited  as  a  mere  point,  is  magnified  in 
length  and  breadth  800  times,  and  the  space  it  occupies  upon  the  paper  is 
640,000  times  greater  than  that  which  it  actually  covered  in  the  fluid  in 
which  it  lived.  This  animalcule  is  globular  in  form,  and  presents  a  glassy  appear- 
ance. It  is  found  in  water  containing  animal  matter,  upon  which  it  feeds  ;  but  as  the 
animal  substance  decomposes  the  monads  die,  and  colorless  jelly-like  masses,  consist- 
ing of  infinite  multitudes  of  their  bodies,  are  seen  with  the  naked  eye  rising  and 
floating  upon  the  surface  of  the  water.  This  creature  is  furnished  with  only  a  single 
organ  of  motion  ;  a  delicate  cilium  issuing  from  its  mouth,  and  by  the  aid  of  this 
member  it  proceeds  through  the  water,  with  considerable  rapidity.  The  twilight 
monad  is  only  the  twenty-four-thousandth  of  an  inch  long,  but  it  sometimes, 
though  seldom,  attains  the  length  of  one-twelve-thousandth  of  an  inch,  which  it 
never  surpasses.  A  single  shot,  one-tenth  of  an  inch  in  diameter,  occupies  more 
space,  than  seventeen  hundred  millions  of  these  living  atoms,  in  their  full  dimen- 
sions, and  exceeds  in  bulk  thirteen  thousand  millions  of  the  smallest  size.  The 


28 


VIEWS    OF    THE    MICROSCOPIC    WORLD. 


conception  of  such  minuteness  is  beyond  the  grasp  of  our  minds  ;  yet  each,  an 
organized  being,  is  not  too  small  to  claim  and  receive  the  regard  of  Him,  who 
called  into  life,  and  amply  endowed  it  with  peculiar  organs  and  powers,  adapted 
to  the  mode  and  range  of  its  existence. 

GRAPE  MONAD. — The  grape  monad,  is  so  called,  from  the  circumstance  that  the 
Fig  9  individuals  at  times,  unite  and  form  clusters,  like  bunches  of  grapes 
or  berries.  A  natural  group  of  a  species  of  this  kind,  is  shown  in 
figure  9,  where  they  are  magnified  linearly  three  hundred  and  fifty 
times  ;  the  diameter  of  the  cluster  being  one-four-hundred  and 
thirtieth  part  of  an  inch,  and  that  of  each  animalcule  one-twenty- 
three-hundredth  of  an  inch. 

This  species  possesses  an  oval  form,  and  is  furnished  with  two  cilia  at  its 
mouth  ;  and  such  is  its  vivacity,  that  notwithstanding  its  minuteness,  it  subsists 
by  prey;  hunting  down,  and  devouring  living  beings  of  inferior  size.  In  1835, 
Ehrenberg  found,  at  one  time,  within  the  body  of  a  grape  monad,  several 
monads,  which  had  fallen  its  victims.  By  feeding  them  with  indigo,  no  less  than 
twelve  stomachs  were  discerned,  as  the  coloring  matter  was  imbibed ;  the  posi- 
tion of  some  of  these  cavities  are  seen  in  the  figure. 

This  animalcule  increases  from  eggs,  which  become  visible  when  magnified 
eight  hundred  times  linearly ;  and  also  by  self-division,  which  takes  place  both 
across  and  lengthwise  of  the  body. 


THE 


Fig.  10. 


GREEN  EYE-MONAD. — In  figure  10,  is  delineated  one  of  the  two  species 
of  the  monads  in  which  a  visual  organ  is  first  discovered.  It  is 
of  an  egg-shaped  form,  and  swims  in  the  direction  of  its  length 
by  the  aid  of  a  cilium  (a  6),  which  is  nearly  as  long  as  the  body. 
Its  color  is  of  a  rich  green,  and  an  eye,  which  is  red,  is  distinctly 
seen,  as  shown  at  c.  This  animalcule  is  found  amid  water-plants, 
and  varies  from  one-seven  hundred  and  twentieth  to  one-twenty- 
three-hundredth  of  an  inch  in  length.  In  the  figure,  it  is  mag- 
nified eight  hundred  times  in  length  and  breadth. 


Fig.  11. 


THE  BREAST-PLATE  ANIMALCULES. — Many  species  of  monads  are  found  clus- 
tered in  one  community,  and  acting  together  with  the  utmost 
harmony.  This  mode  of  existence  occurs  in  the  breast-plate 
monads,  which  have  received  this  name  from  the  form  in  which 
they  are  arranged.  A  group  of  these  singular  creatures  is  shown 
in  figure  11,  and  a  single  animalcule  in  figure  12.  The  breast- 
plate monad  is  found  in  clear  water,  both  salt  and  fresh,  and  con- 
sists of  sixteen  globular  bodies  of  a  pure  green  color,  enclosed 
within  a  flat,  transparent  shell  of  a  pearly  hue.  In  this  they  are 


INFUSORIAL    ANIMALCULES.  29 

regularly  disposed  in  a  square  or  oblong  form,  the  four  central  animalcules  Fig.  12. 
being  usually  larger  than  the  rest.  Their  mode  of  increase  is  by  self-clivi-  W 
sion,  and  when  this  occurs,  the  group  divides  across  the  middle  in  two  © 
directions,  separating  into  four  clusters,  each  containing  four  monads.  No  sooner 
has  a  group  thus  separated,  than  each  of  the  animalcules  which  composed  it, 
increases  in  size,  and  soon  subdivides  into  four  monads,  and  the  original  number 
of  sixteen  is  seen  in  every  one  of  the  four  clusters.  Ere  long,  these  again  sepa- 
rate into  four  portions,  and  the  species  thus  multiply  interminably.  The  tablet, 
though  containing  sometimes  less  than  sixteen  animalcules,  never  exceeds  that 
number.  Its  form  is  often  irregular ;  which  is  caused  by  the  separation  of 
some  of  the  monads  from  the  cluster  when  they  have  attained  their  full  growth. 
Each  of  the  individuals  composing  the  group  is  connected  with  the  rest  by 
means  of  six  threads  or  tubes ;  these,  with  the  two  cilia,  a  and  ft,  are  seen  in 
figure  13,  where  a  monad  is  exhibited  attached  to  a  portion  of  the  p.  13 
transparent  case.  The  length  of  the  tablet  is  not  greater  than  one- 
two  hundred  and  eightieth  of  an  inch,  and  that  of  each  monad 
ranges  from  about  one- five-hundredth  to  one-thousandth  of  an  inch. 
A  single  animalcule,  when  free  from  the  shell,  as  delineated  in  figure 
12,  swims  by  the  aid  of  its  cilia  in  the  direction  of  the  length  of  its 
body,  with  its  mouth  foremost,  as  other  monads  ;  but  the  group 
perform  various  evolutions,  sometimes  proceeding  horizontally, 
sometimes  upwards,  and  again  rolling  on  the  edge  like  a  wheel.  The 
extraordinary  activity  of  these  wonderful  little  beings  is  distinctly  beheld,  when  a 
small  portion  of  coloring  matter,  as  indigo,  is  introduced  into  the  water  in  which 
they  are  discovered  ;  then  whirls  and  currents  will  be  seen  in  the  fluid,  caused 
by  the  vibration  of  the  two  cilia  belonging  to  each  animalcule. 

When  a  group  is  in  progress,  thirty-two  of  these  organs  are  consequently  in 
motion  ;  twenty-four  around  the  edges  of  the  transparent  case,  and  eight  project- 
ing from  the  central  parts,  and  by  their  combined  action,  the  cluster,  enclosed  in 
its  delicate  envelope,  proceeds  as  one  body.  And  here  we  cannot  but  admire 
the  harmonious  action  of  these  curious  groups.  Each  of  the  constituent  indi- 
viduals of  a  cluster  is,  of  itself,  a  perfect  being,  gifted  with  peculiar  powers,  and 
possessing  a  motion  of  its  own ;  yet,  when  united  with  fifteen  others,  all  act  in 
concert,  and  move  through  their  native  element  in  new  modes  of  progression.  In 
the  case  of  the  Siamese  twins,  the  bodies  of  the  two  are  bound  together  by  a 
strong  muscular  band ;  and  when  they  move  in  one  direction  it  is  because 
their  minds  act  in  concert ;  one  cannot  go  north,  when  the  other  wishes  to  go 
south ;  in  order  to  advance  toward  a  given  point,  both  must  resolve  to  do  so.  In 
this  instance,  the  mutual  consent  can  be  readily  expressed  by  words  or  signs ; 
but  who  shall  explain  the  nature  of  that  connexion,  by  which  sixteen  distinct 
animalcules  are  enabled  to  act  with  such  unity  of  purpose,  as  to  effect  a  common 
end ;  moving  upward,  forward,  or  revolving  like  a  wheel,  as  their  pleasure  or 
necessity  demands  ?  Do  they  possess  a  common  instinct  which  actuates  every 
member  of  the  group  at  the  same  moment ;  or  is  each  monad  possessed  of  its 


30 


VIEWS    OF    THE   MICROSCOPIC    WORLD. 


own  independent  and  proper  instinct  ?  This  it  undoubtedly  enjoys,  when  sepa- 
rated from  the  rest ;  and  if  it  is  endued  with  this  when  in  union  with  the  others, 
the  enigma  becomes  still  more  perplexing ;  for  the  question  then  presented  is 
the  following :  What  means  of  intelligent  communication  exist  between  the 
sixteen  distinct  monads  of  a  cluster,  by  which  they  have  the  power  of  acting 
harmoniously,  so  as  to  produce,  at  intervals,  several  common  motions ;  one  of 
which  motions  they  do  not  possess  when  separate  from  the  group  ?  Speculations 
like  these  will  naturally  arise,  when  we  contemplate  such  curious  and  unique 
modes  of  existence ;  but  a  still  more  complex  union  of  individual  life  is  revealed 
in  the  next  species  of  Infusoria  to  be  described. 

THE  REVOLVING  GLOBE-ANIMALCULE. — About  one  hundred  and  fifty  years 
ago,  Leuwenhoeck  discovered  in  water,  an  animated  hollow  globe,  studded  with 
green  specks,  which  advanced  through  the  fluid  with  a  rolling  motion.  It  was 
at  first  supposed  that  the  globe  was  a  single  animal,  but  the  superior  microscopes 
of  the  present  day  have  shown  that  this  is  not  the  case.  The  little  green  specks 
that  gem  the  surface  are  the  true  animals  ;  each  being  a  perfect  monad,  fur- 
nished with  two  cilia,  and  possessing  a  bright  red  eye.  They  are  all  connected 
together,  and  every  individual  is  attached  to  those  immediately  adjacent  by 
delicate  fibres,  varying,  in  number,  from  three  to  six.  The  thousands  thus 
imbedded  throughout  the  entire  surface  of  the  transparent  spherical  shell,  form 
the  hollow  globe,  and  bear  to  it  the  same  relation  as  the  monads  of  the  breast- 
plate cluster  to  their  pellucid  case.  The  whole  globe  bristles  with  the  cilia  of 
the  individual  monads  ;  and  by  the  united  action  of  these  slender  organs,  rolls 
through  the  water  with  the  same  part  always  foremost :  "when  the  fluid  is  colored 
the  current  and  eddies  produced  by  the  cilia  are  clearly  detected.  The  motion 
of  the  cilia  is  regarded  by  Man  tell  as  involuntary,  like  that  of  the  chest  in  the 
act  of  respiration ;  and  he  considers  that  it  subserves  a  similar  purpose,  by 

bringing  the  globe,  with  its  countless  pop- 
ulation, into  contact  with  fresh  portions 
of  water,  from  which  a  constant  supply  of  pure 
air  is  derived,  without  which  these  living  atoms 
must  inevitably  perish.  This  change  of  place 
is  also  necessary  for  the  support  of  the  nu- 
merous groups,  which  range  continually  in  their 
rolling  globe,  through  new  regions  of  space, 
abounding  with  appropriate  food.  In  figure 
14,  the  revolving  globe  is  faithfully  delineated. 
The  minute  dots  with  which  it  is  covered  are 
the  monads  that  compose  it,  and  the  inter- 
lacing net-work  are  the  filaments  which  con- 
nect them  with  each  other.  The  direction  of 
the  globe  in  its  progress  is  indicated  by  the 
arrows,  and  the  cilia  that  propel  it  are  dis- 


Fig.  14. 


INFUSORIAL    ANIMALCULES. 


tinctly  discerned  fringing  its  surface.  Within  the  globe  a  number  of  smaller 
globes  are  perceived ;  and  these  lead  us  to  consider  the  extraordinary  manner  in 
which  these  curious  groups  are  multiplied.  They  increase  by  a  voluntary  separa- 
tion: from  time  to  time  new  spherical  clusters  are  thrown  off  from  the  original  globe; 
not,  however,  from  its  outer  surface,  into  the  surrounding  water,  but  from  the  inner 
surface,  into  the  space  enclosed  by  the  transparent  shell.  Six  or  eight  of  these 
spherical  groups  are  usually  found  within  the  parent  globe ;  though,  at  times, 
as  many  as  twenty  have  been  seen  at  once,  with  their  forms  well  denned,  and 
their  color  of  a  bright  green.  Openings  exist,  both  in  the  primary  sphere  and 
in  the  interior  globes,  through  which  water  passes  and  repasses  for  the  purpose 
of  affording  the  animalcules  fresh  supplies  of -air  and  food.  As  the  young  globes 
increase  in  size,  the  surrounding  envelope  expands,  and  as  soon  as  they  have 
attained  a  certain  degree  of  maturity,  it  bursts  asunder  and  permits  them  to 
escape.  Now,  uncontrolled  in  their  motions,  they  range  through  a  wider  field 
of  existence,  and  soon  a  new  generation  of  revolving  monads  issues  from  their 
parting  spheres ;  to  become,  in  their  turn,  the  parents  of  other  globes,  and  so  on 
in  a  countless  series. 


Fig.  15. 


This  process  of  increase  is  exhibited  in  figure  15,  where 
the  offspring  are  shown  issuing  from  the  parent  sphere,  and 
within  each  of  the  smaller  globes  another  incipient  race  of  re- 
volving animalcules  is  detected.  The  full  sized  globes  are 
one-thirtieth  of  an  inch  in  diameter,  and  the  size  of  the  small- 
est, when  liberated  from  the  parent,  is  one-three  hundred  and 
sixtieth  of  an  inch. 


In  figure  16,  is  delineated  a  portion  of  a  globe  with 
five  single  animalcules  and  a  cluster  of  six  young 
ones  at  a;  they  are  all  attached  to  the  spherical  case,  and 
to  each  other,  and  the  bands  which  connect  them 
together,  as  well  as  their  respective  organs  of  motion, 
are  distinctly  seen. 


In  figure  1 7,  a  single  monad  of  a  revolving  globe,  sepa- 
rated from  its  case,  is  magnified  two  thousand  times;  or, 
in  other  words,  covers  upon  the  paper  a  space  four  mil- 
lion times  greater  than  its  natural  extent.  In  this 
engraving,  the  two  cilia  are  seen  at  6,  6,  the  six  uniting 
threads  at  c,  c,  c,  c,  c,  c,  and  the  eye  of  the  animalcule, 
which  is  of  a  bright  red,  is  situated  at  d.  The  natural 
size  of  a  single  animalcule,  is  the  thirty-Jive  hundredth 
part  of  an  inch.  The  revolving  globe  is  a  common  spe- 
cies of  Infusoria,  and  is  easily  found  in  the  clear  shallow 
waters  of  brooks  and  ponds. 


Fig.  16. 


32 


VIEWS    OF    THE    MICROSCOPIC    WORLD. 


RAY-GLOBE  ANIMALCULES. — Another  kind  of  rolling  Infusoria,  is  delineated  in 
Fig.  is.  figure  18.     They  are  called  the  Ray-Globe  Animalcules,  and 

form,  by  their  union,  a  group  resembling  the  clustering  fruit 
of  the  banana.  Each  animalcule  resides  in  a  cell,  and  the  cells 
of  the  cluster  are  imbedded  in  a  jelly-like  substance  of  a 
spherical  form,  which  rolls  through  the  water  like  the  revolv- 
ing globe.  The  ray-globe  animalcule  is  of  a  yellow  color,  is 
provided  with  two  organs  of  motion,  but  not  with  an  eye  ;  and 
is  likewise  furnished  with  a  slender  tail,  by  which  it  is  con- 
nected, either  with  the  centre  of  the  cluster,  or  with  the  bottom 
of  its  own  cell.  This  latter  member  possesses  the  curious  property  of  extension  and 
contraction,  and  by  its  aid  the  animalcule  can  protrude  itself  beyond  its  cell,  to  a 
distance  equal  to  three  times  its  natural  length,  and  then  at  its  pleasure  withdraw 
again  into  its  apartment. 

Figure  19  is  a  magnified  portion  of  a  cluster,  and 
displays  the  manner  in  which  the  tails  of  the  creatures 
are  connected  with  the  common  covering.  The  length 
of  a  single  animalcule  of  this  kind,  exclusive  of  its  tail,  is 
one-seventeen  hundredth  of  an  inch  /  and  the  size  of  a 
cluster  varies  from  one-one  hundred  and  ninetieth  part  of 
an  inch  to  one-two  hundred  and  eightieth. 

THE  BLOOD-LIKE  ASTATIA. — This  animalcule  belongs  to  a  kind,  which  has 
received  the  name  of  Astatia,*  from  the  circumstance  that  they  have  no  fixed 
abode  like  the  globe  animalcules  ;  but  are  endowed  with  perfect  freedom  of  mo- 
tion. They  have  the  power  of  changing  their  form  at  pleasure,  are  destitute  of 
an  eye,  and  move  from  place  to  place  by  means  of  a  tail,  and  a  delicate,  vibrating 
cilium.  These  animated  particles  are  sometimes  produced  in  such  vast  numbers 
as  to  dye  the  waters  in  which  they  live  with  a  crimson  hue. 

Fi    ^  The  blood-like  Astatia  is  delineated  in  figure  20.     Its 

body,  when  extended,  is  spindle-shaped,  as  there  exhibited  ; 
at  first,  the  animalcule  is  green,  but  afterwards  assumes 
blood-red  color.    Figure  2 1  shows  an  individual  of  the 
ame  species  with  the  body  contracted.     The  length  of 
this  little  creature  is  one- three  hundred  and  eightieth  of 
an  inch. 

Fig.  21. 

THE  BLOOD-RED  EYE  ANIMALCULE. — This  animalcule  belongs  to  the  same 
family  as  the  Astatia,  but  differs  from  it  in  possessing  a  beautiful  reel  eye.  It 
varies  in  length  from  one-two  hundred  and  fortieth  to  one-three  hundredth  of  an 
inch,  and  is  of  an  oblong  shape  ;  but  is  capable  of  changing  its  form  at  will.  This 

*  Greek,  a,  privative,  without ;  stasis,  a  station,  hence  Astatia. 


INFUSORIAL    ANIMALCULES. 


33 


curious  characteristic  is  recognised  in  figures  22,  23,  and  24,  where  the  animal- 
cule is  delineated  under  the  various  shapes  it  assumes.     During  the  early  stages 
of  its  existence,  its  color  is  green  ;  but  upon  arriving  at  maturity  it  is  of  a  blood- 
Fig.  22.  Fig-  24. 

Fig.  23. 


Fig.  25. 


red  hue.  Individuals  are  seen,  however,  partaking  of  both  hues,  being  variegated 
with  red  and  green  spots.  This  variation  in  color  is  attributed  by  Ehrenberg  to 
the  condition  of  the  eggs  belonging  to  the  creature,  which  appear  of  different 
colors  at  different  times,  covering  the  stomach-cells.  This  animalcule  swims 
through  the  water  with  a  -slow  motion,  by  the  aid  of  a  thread-like  cilium,  which 
is  seen  in  figure  23  ;  and  the  currents  produced  by  this  organ,  and  which  are 
discernible  when  the  water  is  colored,  are  delineated  in  figure  22.  In  figure  24, 
where  the  cilium  appears  double,  the  animalcule  is  on  the  point  of  dividing  into 
two,  and  a  single  organ  belongs  to  each  of  these  parts  which  are  soon  to  become 
independent  beings.  Not  only  does  this  animalcule  swim  in  a  straight  line  through 
the  water  ;  but  it  also  proceeds  on  its  course  by  rolling  over  and  over  sideways. 
It  is  frequently  found  congregated  in  vast  numbers,  clothing  with  a  crimson 
mantle  the  surfaces  of  ponds  and  stagnant  waters. 

THE  FLOWERING  CUP-ANIMALCULES. — In  figures  25  and  26,  a  species  of  In- 
fusoria is  exhibited,  which  appears  in  the  shape  of  a  branch ; 
formed  of  a  series  of  cups  united  to  each  other. 

The  cup  is  nothing  more  than  a  delicate,  pellucid  shell,  en- 
closing an  animalcule  which  is  attached  to  the  bottom.  The 
living  atom,  with  its  encircling  case,  is  distinctly 
seen  in  figure  26.  It  is  of  a  pale  yellow  tint, 
and  is  furnished  with  a  red  eye,  the  position  of 
which  is  indicated  by  the  oval  spot  near  the  head 
of  the  animalcule  ;  and  far  beyond  the  margin 
of  the  shell  protrudes  a  slender  cilium.  The 
flowering  cup-animalcule  has  the  power  of  alter- 
ing its  form,  and  at  one  time  is  seen  contracting 
itself  into  a  round  figure  at  the  bottom  of  its  cup, 
and  at  another,  extending  its  body  as  far  as  the  edge  of  its 
shell,  which  is  its  utmost  limit. 

This  kind  of  Infusoria  multiply  by  means  of  little  cups, 
which  are  seen  budding  from  the  parent ;  and  thus  it  contin- 
ues to  increase,  until  at  length  a  living  branch  is  developed  of  considerable  size. 

3 


Fig.  26. 


34 


VIEWS    OF    THE    MICROSCOPIC    WORLD. 


In  figure  25,  such  a  cluster  is  seen  containing  eight  animalcules,  and  the  shells 
of  three  which  have  perished.  The  motion  of  the  vibrating  cilia  is  indicated  by 
the  currents  ;  and  through  the  united  and  harmonious  action  of  these  strange 
organs,  the  entire  branch  of  animated  atoms  proceeds  as  one  bodv  through  the 
water. 

This  animalcule  is  found  in  the  water  of  swamps  ;  its  length  is  about  one-five 
hundred  and  seventieth  part  of  an  inch,  and  that  of  a  cluster  one-one  hundred 
and  twentieth  of  an  inch. 

THE  PROTEUS.— In  figures  27,  28,  and  29,  a  most  remarkable  animalcule  is  exhi- 
Fig- 28>  Fig.  27.  bited,  which  varies  in  size 

from  one-one  hundred  and 
fortieth,  to  one-seventieth 
of  an  inch  in  length. 

It  appears  under  the 
microscope  as  a  pale  yel- 
low mass  of  jelly-like  mat- 
ter, and  is  endued  with 
the  power  of  changing  its 
shape  to  a  very  extraordi- 
nary degree,  as  is  obvious 
from  the  inspection  of  the 
figures.  From  this  circum- 
stance it  is  termed  the 
Proteus  ;  the  name  of  the 
Fig.  29.  wondrous  sea-god,  who 

could  assume  at  will,  every  form,  turning  himself  into  animals,  trees,  fire,  and 
water  ;  according  to  the  fables  of  the  classic  poets. 

The  Proteus  can  hardly  be  said  to  possess  any  original  shape  ;  for  it  is  capa- 
ble of  relaxing  itself  in  one  place,  and  contracting  in  others ;  and  of  pushing 
out  from  every  part  of  its  body  long  arms  and  feelers,  (a  a  a,  &c.)  which  are  its 
organs  of  motion,  to  the  number  of  ten  or  twelve  at  one  time.  These  members 
the  animalcule  can  again  withdraw  into  its  body,  and  protrude  others  from  a  dif- 
ferent place,  if  it  pleases  so  to  do.  This  animalcule,  like  those  which  have  already 
been  described,  is  polygastric  in  its  structure,  and  its  numerous  stomachs  are  visi- 
ble even  in  their  natural  state ;  but  their  position  and  form  is  more  clearly  seen 
when  distended  with  a  colored  fluid. 

In  the  figures,  their  situations  are  indicated  by  the  larger  cavities,  (b  b  6,  &c.)  and 
are  represented  as  they  exist,  dispersed  throughout  the  body  of  the  creature. 

BACILLARIA,  OR,  STICK-ANIMALCULES. — We  now  proceed  to  the  examination 
of  a  species  of  a  numerous  class  of  existences,  which  are  found  in  all  waters  both 
salt  and  fresh,  and  which,  from  the  appearances  they  exhibit,  are  termed  Bacilla- 
ria ;  from  the  Latin  word  bacillum,  a  little  stick.  They  are  called  existences, 


INFUSORIAL    ANIMALCULES.  35 

because  naturalists  have  not  yet  been  able  to  determine  whether  they  are  animals 
or  vegetables.  The  first  observers  regarded  them  as  animals  ;  but  the  greater 
number  of  modern  microscopists  believe  them  to  be  vegetables ;  while  others 
consider  many  of  these  existences  to  be  the  connecting  links  between  the  animal, 
vegetable,  and  mineral  kingdoms.  Dr.  Ehrenberg,  whose  opinion  is  entitled  to 
very  great  weight,  affirms  that  they  are  undoubtedly  of  animal  origin ;  while,  on 
the  contrary,  Dr.  Meyen  declares  "  that  much  observation  is  yet  wanting,  ere  we 
can  hope  satisfactorily  to  determine  that  the  Bacillaria  are  truly  animals." 
Whether  animals  or  plants,  these  existences  are  beautiful  and  interesting  micros- 
copic objects ;  and  without  presuming  to  pronounce  upon  this  disputed  point,  on 
which  far  abler  judges  differ,  we  shall  follow  the  classification  of  Ehrenberg,  and 
speak  of  them  as  animals. 

THE  GALLIONELLA,  OR  BOX-CHAIN  ANIMALCULES. —  This  division  of  the  Bacil- 
laria has  been  termed  Gallionella,  from  Gaillon,  a  French  naturalist ;  and  has 
also  received  the  appellation  of  box-chain  animalcules  from  the  form  in  which 
they  are  developed.  They  are  each  invested  with  a  flinty  case,  consisting  of  two 
shells  ;  the  case  being  cylindrical  in  form,  and  when  lying  upon  its  face  present- 
ing the  appearance  of  a  coin.  The  cylindrical  cases  are  arranged  in  chains,  in 
consequence  of  the  imperfect  self-division  of  the  animalcule,  whereby  the  young, 
as  they  are  successively  produced,  remain  attached  to  the  parent  stock.  The 
Gallionella  are  found  both  in  a  living  and  in  a  fossil  state,  and  in  the  latter 
afford  very  rich  objects  for  the  microscope.  They  are  exceedingly  abundant, 
existing  in  every  pool,  river,  and  lake  ;  and  such  are  their  astonishing  powers  of  in- 
crease, that  one  hundred  and  forty  millions  of  millions  will  spring  from  a  single 
specimen,  by  self-division,  in  twenty-four  hours. 

Fig.  30. 

THE  STRIPED  GALLIONELLA. — This  species  of  the  box-chain  animalcules 
is  delineated  in  figure  30,  which  represents  a  specimen  found  by  Dr. 
Mantell,  in  a  pond  near  London.  Several  distinct  Infusoria,  invested  in 
their  flinty  cases,  are  here  beheld  forming  a  chain,  which  is  highly 
magnified.  The  fine  lines  running  across  the  living  links  of  the  chain 
are  in  the  direction  of  the  length  of  the  animalcules,  and  the  position 
of  the  eggs,  which  are  yellow  and  green,  is  indicated  by  the  small  cir- 
cles distributed  throughout  the  entire  chain.  The  striped  Gallionella 
is  found  both  in  fresh  and  salt  water,  and  varies  in  size  from  one-four- 
teen  hundredth  to  one-four  hundred  and  thirtieth  of  an  inch.  The 
latter  length  is  the  natural  size  of  the  engraved  specimen.  Single 
chains  are  sometimes  found  three  inches  in  length,  consisting  of  from 
1200  to  4000  animalcules. 


36 


VIEWS    OF    THE    MICROSCOPIC    WORLD. 


THE  RUST-LIKE  GALLIONELLA. — In  figures  31  and  32  are  shown  several  deli- 
Fig.  31.  Fig.  32  cate  an<^  branching  chains,  composed  of  these  little  beings, 
which,  from  the  resemblance  of  their  color  to  that  of  iron- rust, 
!  have  received  the  name  of  Rust-like  Gallionella.  Each  of  these 
1i  Infusoria  is  invested  with  a  flinty  shell,  of  an  oval  shape,  round- 
ed at  both  ends  and  smooth  on  the  surface.  They  are  found  in 
most  of  the  waters  impregnated  with  iron,  and  also  in  peat- 
water,  which  contains  a  little  of  this  mineral.  Every  thing 
beneath  the  surface  is  covered  by  these  creatures  in  countless 
numbers,  forming,  by  their  union,  a  light  mass  composed  of 
such  delicate  flakes,  that  it  is  dispersed  by  the  slightest  motion. 
In  the  spring,  this  flocculent  substance  consists  of  short  chains 
of  pale-yellow  globules,  strung  together  like  rows  of  beads,  which  can  be  readily 
separated  from  each  other.  Their  union,  however,  is  detected  with  difficulty  at 
this  time  ;  but  as  the  season  advances,  the  Infusoria  become  more  developed,  and 
their  structure  is  better  discerned  :  when  summer  arrives,  the  threads  and  chains 
of  which  the  whole  mass  is  woven,  yield  to  the  power  of  the  microscope,  and  the 
texture  is  more  clearly  revealed  to  the  eye.  At  this  period,  the  color  of  this 
animalcule  is  of  a  deep  rusty-red ;  but  in  the  spring,  its  tint  is  that  of  a 
pale-yellow  ochre.  This  species  of  Infusoria  is  found  both  in  a  recent  and  fossil 
state,  and  measures  only  one-twelve  thousandth  of  an  inch  in  diameter. 

THE  NAVICULA,  OR  LITTLE-SHIP  ANIMALCULES. — This  kind  of  Infusoria  belongs 
to  the  Bacillaria,  and  is  shaped  like  a  boat  or  ship,  and  from  this  resemblance 
has  received  the  name  of  Navicula,  which  in  the  Latin  language  signifies  a  little 
ship.  They  are  never  united  like  the  Gallionella,  in  chains  ;  but  exist  singly  and 
in  pairs,  enclosed  in  a  durable,  thin,  siliceous  shell,  generally  four-sided,  and 
which,  when  slightly  pressed,  divides  either  into  two  or  four  parts,  disclosing 
the  appearance  of  ribs  running  across  it.  A  jelly-like  substance,  which  con- 
stitutes the  body  of  the  animal,  occupies  the  interior  of  the  shell,  and  portions 
of  matter,  of  a  green,  yellow,  and  brown  color  are  here  perceived,  which  have 
been  regarded  by  naturalists  as  the  eggs  of  the  Navicula.  Many  of  the  ship- 
animalcules  propagate  by  self-division  in  the  two  directions  of  their  length  and 
breadth  ;  the  separation  commencing  in  the  soft  body  beneath  the  shell,  which 
afterwards  divides  into  parts  corresponding  to  those  of  the  body.  Twenty-four 
different  kinds  of  fossil  Navicula  have  been  discovered,  fourteen  of  which  have 
been  identified  with  species  now  living. 

GREEN  NAVICULA. — Figure  33  is  a  drawing  of  this  animalcule,  representing 
a  specimen  taken  by  Dr.  Mantell  from  a  pool  in  Clapham  Common,  in  the  vicinity 

of  London.     The  small  dots  are  the  stom- 
ach-cells of  the  creature,  and  the  rib-like 
o-o-i?-o^sCSS^:a'i^i>^   divisions   of  the  shell   are    distinctly  seen 
throughout  its  whole  extent.    So  numerous 


INFUSORIAL    ANIMALCULES. 


are  they,  that  fifteen  are  contained  within  Fi=-  34< 

every  twelve  hundredth  of  an  inch  in  length. 
A  side  view  of  the  same  animalcule  is 
shown  in  Figure  3  4,  exhibiting  the  currents 
produced  by  its  motion  through  the  water. 
This  species  of  Navicula  varies  in  size  from  one-seventieth  to  one-one  hundred  and 
fifteenth  part  of  an  inch  in  length. 

GOLDEN  NAVICULA. — Figures  35  and  36  are   representations  of  a  beautiful 
species  of  the  golden  Navicula,  so  called,  because  Fig.  35. 

the  clusters  of  eggs  within  the  shell  are  of  a 
bright  yellow  color.  They  are  seen  in  the  engra- 
ving occupying  the  central  portions  of  the  shell, 
and  filling  up  its  numerous  flutings.  The  shell  is 
of  an  oblong  oval  shape,  and  possesses  the  utmost 
regularity  in  its  structure.  In  figure  35,  the  ani- 
malcule is  seen  from  above  ;  in  Figure  36,  a  side 
view  of  the  same  creature  is  presented  :  by  com- 
paring the  two  drawings,  it  is  seen  that  the  shell 
tapers  more  in  the  latter  case  than  in  the  former. 
The  above  figures  are  faithful  delineations  of  a  living  golden  Navicula,  obtained 
by  Dr.  Man  tell :  the  length  of  this  specimen  was  found  to  be  the  one  hundred  and 
forty-fourth  part  of  an  inch.  This  species  varies  in  size,  however,  from  one-one 
hundredth  to  one-two  hundred  and  tenth  of  an  inch. 

THE  SWOLLEN  EUNOTIA. — In  figure  37  is  shown  the  shell  of  a  species  of  ani- 

Fig.  37. 


Fig.  36. 


Fig.  38. 


malcule,  which  differs  a  very  little  in  its  characteristics  from  those  just  described. 
It  is  called  the  Swollen  Eunotia.  The  shells  vary  in  length  from  one-eleven 
hundred  and  fiftieth  of  an  inch  to  one-two  hundred  and  fortieth,  and  are  of  the 
shape  represented  in  the  figure,  which  exhibits  a  side  view.  A  furrow  (a,  a,)  runs 
the  whole  length  of  the  shell,  along  the  middle  of  each  side*  and  from  this  fur- 


38 


VIEWS    OF    THE    MICROSCOPIC    WORLD. 


Fig.  39. 


row,  numerous  curved  ribs  branch  out  towards  either  edge.  The  furrows  are 
plainly  discerned  in  the  shell ;  but  are  detected  with  difficulty  in  the  living 
Infusoria,  on  account  of  the  color  of  the  body.  So  closely  are  the  ribs  placed 
together,  that  no  less  than  eight  are  contained  within  the  space  of  one-twelve 
hundredth  of  an  inch  Figure  38  is  the  representation  of  several  living  animal- 
cules of  this  species,  found  upon  a  branch  of  conferva,  which  is  the  bright  green 
vegetable  matter  that  floats  upon  stagnant  waters  during  the  spring  and  summer. 
The  Eunotia  multiplies  by  self-division,  and  in  figure  39  an  individual  is  exhibited 

undergoing  this  process.  The 
separation  is  seen  to  take  place 
in  the  direction  of  the  length, 
|a  and  in  each  half  we  can  discern 
another  line  of  division,  (a,  a;  6, 
$  &,)  just  commencing.  Through 
this  line,  when  the  divided  por- 
tions have  arrived  at  maturity,  and  each  has  become  a  perfectly  developed 
animalcule,  another  separation  occurs,  and  thus  proceeds  interminably. 

XANTHIDIA  OR.  DOUBLE-BAR  ANIMALCULES. — This  kind  of  Infusoria  are  en- 
closed in  a  transparent,  single-valved  shell,  of  a  globular  shape,  which  resists  the 
action  of  fire,  and  is  studded  with  spines  or  thorns :  a  green  mass  is  seen  in  the 
interior  that  is  supposed  to  be  the  eggs  of  the  creature.  The  bar-animalcules 
exist  both  in  a  living  and  fossil  state,  and  are  found  abundantly  in  flint,  as  will 
be  shown  hereafter.  They  exist  singly,  in  pairs,  and  in  groups  of  four,  and  in- 
crease by  self-division.  Two  figures  of  living  Xanthidia  are  displayed  in  figures 
40  and  41.  Figure  40  is  a  drawing  of  a  forked  bar-animalcule,  Fig  40 
found  by  Dr.  Bailey  in  a  pond  near  West  Point :  its  shell  is 
green  and  of  an  oval  form,  and  its  natural  length  is  one- two  hun- 
dred and  eighty-eighth  of  an  inch. 

Fig.  41.  Figure  41  is  a  different  species,  and  represents 

a  spinous  Xanthidium,  obtained  by  Dr.  Mantell 
from  a  pond  in  Clapham  :  it  is  of  the  same 
size  as  the  preceding  specimen,  and  is  likewise 
of  a  beautiful  deep  green  hue. 

THE  PYXIDICULA,  OR  ROUND  BOX-ANIMALCULES. — These  minute  creatures  have 

Fig.  42.      Fig.  43.   received  their  scientific  name  from  their  form — pyxidicula  sig- 

b     nifying,  in  the  Latin  language,  a  little  box.     They  are  enclosed 

®in  a  transparent,  spherical,  flinty  case,  which  is  marked  by  a 
circular  furrow,  through  which  it  readily  divides,  separating  into 
two  hemispheres.  A  group  of  a  living  species  of  the  Pyxidi- 
cula is  delineated  in  figures  42,  43,  and  44  :  a  is  a  view  of  the 
shell  at  right  angles  to  that  presented  at  £>,  and  exhibits  the  fur- 
row through  which  it  separates  ;  and  c,  is  one  of  the  two  hem- 
ispheres into  which  the  shell  divides.  This  animalcule  is  of  a 


Fig.  44. 


INFUSORIAL    ANIMALCULES. 


39 


Fig.  46. 


yellowish  green  color,  and  varies  in  length  from  one-fourteen  hundred  and  fortieth 
of  an  inch  to  one-Jive  hundred  and  seventieth.  It  is  quite  common,  and  is  found 
both  in  a  living  and  fossil  condition. 

Fig.  45. 

THE  ZIGZAG  ANIMALCULES. — Figure  45  is  a  drawing 
of  a  common  Zigzag  animalcule,  found  by  Dr.  Mantell 
in  the  neighborhood  of  London.  These  Infusoria  have 
received  the  above  appellation  in  consequence  of  their 
being  developed  in  zigzag  chains,  each  link  consisting  of  a  living  creature.  This 
mode  of  union  arises  from  the  circumstance,  that  although  the  shells  of  all  the 
animalcules  are  perfectly  separated,  their  bodies  are  not,  and  thus  remaining  at- 
tached, they  present  to  view  an  irregular  series,  such  as  is  displayed  in  the  figure. 
The  flinty  shell  is  three  or  four  times  as  long  as  it  is  broad,  is  prismatic  in  shape, 
and  contains  thirteen  cross  lines  in  every  twelve  hundredth  of  an  inch.  A  nar- 
row opening  runs  from  one  end  of  the  shell  to  the  other,  through  which  soft, 
fleshy  members  are  protruded,  by  the  aid  of  which  locomotion  is  effected.  The 
natural  size  of  each  shell  of  the  chain  in  the  engraving,  is  one-four  hundred  and 
thirty-second  part  of  an  inch.  \ 

In  figure  46,  is  shown  a  cluster  of  another  species  of 
these  animalcules,  which,  when  imperfectly  divided,  are 
attached  side  by  side,  and  slide  one  upon  the  other — the 
entire  group  shortening  and  lengthening  itself  at  plea- 
sure. Their  color  is  of  an  orange  yellow,  and  their 
length  varies  from  one-two  hundred  and  fortieth  of  an 
inch  to  one-eleven  hundredth. 

THE  PALM,  FAN-SHAPED  ANIMALCULE. — A  species  of  Infusoria  belonging  to 
the  family  of  the  Bacillaria  and  bearing 
the  above  name,  is  shown  in  figure  47. 
These  animalcules  are  encased  in  a  shell 
which  is  broad  and  wedge-shaped,  and 
form  a  fan-like  cluster,  rising  from  a  single 
trunk  or  stalk.  The  stalk  is  produced  by  an 
excretion  of  the  animalcule,  and  is  not  pos- 
sessed of  any  vital  power :  for  if  the  branch- 
ing, living  groups  are  broken  off,  no  fresh 
buds,  teeming  with  animal  life,  are  put  forth 
from  the  mutilated  trunk,  but  it  soon  crum- 
bles away  and  utterly  perishes.  This  ani- 
malcule increases  by  a  longitudinal  self-divi- 
sion, but  the  separation  does  not  extend  to 
the  stalk  ;  for  this  remains  entire  while  the 
creature  continues  to  develope  in  fan-shaped 
groups,  the  trunk  branching  into  thick  ge- 
latinous boughs,  to  which  the  separate  ani- 


Fig.  47. 


Fig.  48. 


40 


VIEWS    OF    THE    MICROSCOPIC    WORLD. 


mated  atoms,  gleaming  with  a  golden  hue,  are  attached  like  fruit  by  a  slender 
stem.  This  animalcule  is  found  covering  the  surface  of  marine  plants.  The 
natural  size  of  the  cluster  varies  from  one-twelfth  to  one-sixth  of  an  inch — that 
of  a  single  specimen  is  one  one-hundred  and  twentieth  of  an  inch.  Figure  48 
is  a  back  and  side  view  of  a  single  animalcule,  highly  magnified. 

THE  BELL-SHAPED  ANIMALCULES. — This  family  of  Infusoria,  which  is  remarka- 
ble for  the  graceful  elegance  of  its  forms,  is  devoid  of  a  shell ;  and  each  individual, 
when  unconnected  with  others,  roams  about  in  solitary  independence.  When, 
however,  they  are  attached  to  a  stem,  they  live  together  in  great  numbers, 
assuming  the  shape  of  trees  or  shrubs,  with  an  animalcule  appended  like  a  flower 
to  the  extremity  of  every  tiny  spray.  Imperfect  self-division  gives  rise  to 
these  beautiful  tree-like  clusters ;  but,  in  addition  to  this  mode  of  increase,  they 
likewise  multiply  by  the  growth  of  buds,  either  from  the  sides  of  the  animalcules, 
or  from  the  stalks  to  which  they  are  united.  The  Bell-shaped  animalcules  are 
usually  found  clustered  together,  in  countless  numbers,  upon  the  submerged 
Fi  49  surfaces  of  twigs  and 

roots.  They  adhere  also 
to  the  small  leaves  of  the 
duck- weed,  and  attach 
themselves  to  the  shells 
of  minute  aquatic  ani- 
mals ;  but  when  fully  de- 
veloped, they  are  gene- 
rally connected  with  some 
fixed  object.  A  group 
of  several  animalcules  be- 
longing to  this  family,  and 
of  the  species  termed  the 
Nebulous  bell-shaped  ani- 
malcule, is  exhibited  in 
figure  49.  The  body 
of  the  creature,  as  its 
name  implies,  has  the 
shape  of  a  bell,  the  mar- 
gin of  which  is  fringed 
with  a  circle  of  cilia.  The 
space  surrounded  by  the 
cilia  is  the  mouth  of  the  an- 
imalcule, and  the  position 
of  its  stomachs  is  marked 
by  the  round  spaces  within 
the  bell.  The  slender  stem  by  which  each  individual  of  a  group  is  attached  to 
a  common  base,  is  furnished  with  a  long  and  delicate  muscle,  traversing  its  entire 


INFUSORIAL    ANIMALCULES.  41 

length,  by  the  aid  of  which  it  is  alternately  extended  and  shortened.  The  ani- 
malcule, at  the  approach  of  danger,  coils  up  its  tiny  cable  with  the  quickness  of 
thought,  sinking  down  towards  the  spot  where  it  is  anchored ;  and  then  again  when 
the  peril  is  past,  floats  upwards  in  search  of  food,  and  swings  once  more  to  the 
utmost  extent  of  its  line.  This  contractile  action,  as  Mantel!  remarks,  is  contin- 
ually going  on — now,  in  one  or  two  individuals  only,  then  in  several,  and  often 
the  whole  group  suddenly  shrinks  down  into  a  confused  mass,  and  the  next 
instant  expands,  and  every  little  bell  becomes  fully  developed,  with  its  cilia  in 
rapid  oscillation. 

The  group  in  the  figure  represent  a  number  of  animalcules,  of  this  species,  in 
different  attitudes  and  conditions.  Some  have  their  stalks  stretched  to  the 
utmost  length,  with  their  crowns  of  cilia  in  full  action,  while  others  have  their 
stems  more  or  less  coiled.  Many  are  single,  and  others  (a  a  a,)  have  divided 
into  two,  and  the  stems  of  several  are  seen,  from  which  the  animalcules  have 
broken  and  swam  away.  The  length  of  the  body  of  this  species  varies  from  one- 
two  hundred  and  eightieth  of  an  inch  to  one- five  hundred  and  seventieth. 

The  self-division  of  these  Infusoria  proceeds  as  follows :  The  bell  first  begins 
to  expand  in  breadth,  and  then  a  separation  commences  extending  in  the  direc- 
tion of  its  length,  double  rows  of  cilia  becoming  meanwhile  formed.  At  length, 
the  two  parts  being  perfectly  developed,  the  bell  divides  into  two  animalcules,  and 
fringes  of  cilia  next  appear  encircling  the  base  of  each.  Soon  the  young  animal- 
cules twist  off  from  the  stem  which  speedily  decays,  and  after  swimming  about 
for  some  time,  at  last  put  forth  a  new  stem  from  the  end  of  each  bell ;  then  fix- 
ing themselves  to  some  object,  they  multiply  by  self-division,  and  become  in 
their  turn  the  progenitors  of  a  numerous  race. 

In  figure  50,  two  bell-shaped  animalcules  are  seen,  which  Fis- 

have  just  been  produced  from  one  by  separation,  each  being 
still  attached  to  the  parent-stem  by  its  own  stalk. 

The  advantage  resulting  from  the  use  of  a  colored 
fluid,  in  enabling  the  observer  to  detect  the  stomach-cells 
of  minute  Infusoria,  has  already  been  mentioned  more  than 
once  ;  but  the  following  detail  of  its  employment  by  Dr. 
Mantell,  when  experimenting  upon  Bell-shaped  Infusoria, 
is  too  instructive  to  be  omitted.  "  I  place,"  says  this  inter- 
esting writer,  "a  drop  of  a  solution  of  carmine  in  the  water  between  the 
plates  of  glass  containing  these  animalcules ;  the  fluid  in  which  they  are 
floating  now  appears  turbid,  and  full  of  gray  particles,  which  are  thrown  into 
rapid  motion  by  the  vibrations  of  the  cilia,  and  currents  are  seen  passing 
to  and  fro  from  the  mouths  of  the  animalcules.  In  a  few  minutes  the 
water  gradually  becomes  clear,  and  several  round  spots  of  carmine  are 
apparent  in  the  body  of  each  animalcule.  We  have,  in  fact,  caused  their 
little  stomachs  to  be  filled  with  coloring  matter,  and  can  now  distinguish  their 
number  and  arrangement.  If  the  body  of  the  animalcule  were  a  mere  cavity,  it 
is  obvious  that  the  carmine  must  have  collected  into  a  single  ball  or  mass  ;  but 


42  VIEWS    OF    THE    MICROSCOPIC    WORLD. 

this  is  not  the  case  ;  on  the  contrary,  the  color  appears  in  distinct  round  spots, 
from  having  accumulated  in  globular  cells,  and,  by  careful  investigation,  the  tube 
connecting  these  cells  may  be  detected." 

THE  TREE-ANIMALCULES. — The  Bell-shaped  Infusoria,  which  have  just  been 
described,  are  each  attached  to  a  common  base,  by  a  separate  stalk ;  but  in  the 
kind  we  are  now  considering  the  entire  cluster  springs  from  a  single  trunk, 
which,  dividing  and  subdividing  into  numerous  branches,  puts  forth  its  trumpet- 
shaped  living  blossoms,  at  the  extremity  of  every  bough.  This  mode  of  union 
is  the  result  of  imperfect  self-division — a  single  animalcule  first  separating  into 
two,  that  are  united  by  a  forked  stem,  and  these  again  into  four,  which  still 
remain  connected ;  thus  the  division  proceeds,  until  the  limit  of  development  is 
attained,  and  a  graceful,  branching  cluster  rises  from  a  common  stalk.  The  spon- 
taneous separation  of  the  individual  creatures  is  effected  in  the  manner  already 
detailed,  and,  as  in  the  case  of  their  kindred  species,  the  Tree-animalcule,  upon 
arriving  at  maturity,  breaks  away  from  the  parent  stock,  and  the  single  living 
cup,  floating  for  awhile,  at  length  becomes  stationary,  and  a  new  generation  of 
arborescent  forms  are  produced,  by  their  repeated  self-division.  These  Infusoria 
have  also  been  observed  to  multiply  by  the  growth  of  buds. 

The  Tree-animalcule  is  shown  in  figures  51  and  52.     In  the  latter  engraving 
the  beautiful  group  is  seen  fully  developed,  with  the  trumpet-shaped  animals 
clustering  on  every  branch  ;  their  circles  of  cilia  expanded  to  the  utmost,  and 
Fig.  si.  tne  position  of  their  stomach-cells  clearly  indicated  by  the 

round  spaces  within  their  bodies.  A  muscle  is  distinctly 
seen  rising  from  the  root,  traversing  the  trunk,  and  extend- 
ing its  minute  ramifications  to  every  member  of  the 
group.  Not  only  is  each  individual  endowed  with  the 
power  of  coiling  and  uncoiling  its  own  stalk,  by  the  aid 
of  this  muscle,  independently  of  the  action  of  its  fellows, 
as  shown  in  the  cut,  but  the  whole  group  can  suddenly  con- 
tract its  dimensions,  the  main  trunk  folding  closely  together 
in  spiral  wreaths,  and  the  spreading  tree  shrinking  into  a 
globular  mass,  while  each  animalcule  assumes  a  spherical 
shape,  and  its  crown  of  cilia  occupies  a  narrower  circle. 
This  attitude  of  the  group  is  exhibited  in  figure  51.  The 
natural  size  of  a  single  animalcule  ranges  from  one-four 
hundred  and  thirtieth  of  an  inch  to  one-Jive  hundred  and  seventieth. 

The  living  forms  that  constitute  the  Infusorial  world,  bear,  for  the  most  part, 
little  or  no  resemblance  to  those  that  are  visible  to  the  unaided  eye  ;  but  in  the 
beautiful  groups  we  have  just  considered  it  is  otherwise  ;  for,  in  their  curious 
figures  and  organization,  that  type  of  animal  existence  is  recognised,  which  adorns 
the  ocean  with  living  flowers,  and  peoples  its  azure  depths  with  a  thousand 
arborescent  forms ;  where  a  sensitive  life  is  enshrined  in  each  bud,  and  which, 
developed  in  its  countless  generations,  spreads  through  the  waters,  a  mazy  grove. 


INFUSORIAL    ANIMALCULES. 


TRUMPET  ANIMALCULES,  (Stentors.)— This  division  of  the  family  of  the  Bell- 
shaped  Infusoria  receives  its  name  from  its  peculiar  form,  which  resembles  that 
of  a  trumpet.  Unlike  most  of  the  Fig.  52.  . 

race  to  which  it  belongs,  the  Stentor  is 
destitute  of  a  stalk,  and  attaches  itself 
by  the  lower  extremity,  in  the  manner 
of  a  leech,  to  the  different  substances 
it  meets  with  in  the  water.  Its  whole 
body  is  covered  with  cilia,  and  a  spiral  | 
wreath  of  these  organs  is  seen  sur- 
rounding the  expanded  mouth.  By 
the  aid  of  these  members  the  Stentor 
moves  swiftly  through  the  water,  and 
at  the  same  time  sweeps  within  its 
grasp  the  various  living  atoms  upon 
which  it  preys.  This  creature  is  very 
voracious  and  devours  great  quanti- 
ties of  monads,  wheel-animals,  and 
other  Infusoria.'  These  are  frequent- 
ly found  within  its  stomachs,  which 
are  arranged  like  the  beads  of  a  neck- 
lace. This  chain  of  stomachs  proceed- 
ing from  the  mouth,  traverses  the  body 
of  the  Stentor  in  the  direction  of  its 
length,  and  returning,  unites  with  it  in 
a  spiral-shaped  cavity.  They  increase 
by  self-division,  either  lengthwise  or 
obliquely,  and  also  from  eggs  which 
vary  in  color  in  different  kinds.  There 
are  several  species  of  the  Trumpet-ani- 
malcules, which  are  dissimilar  both  in 
size  and  color.  Some  of  them  are 
sufficiently  large  to  be  detected  by  the  naked  eye,  but  the  microscope  is  needed 
for  their  full  examination.  Their  colors  are  blue,  vermilion,  green,  yellow,  and 
brown.  In  figure  53,  a  group  of  a  species,  termed  the  Many-shaped  Stentor  is 
delineated,  adhering  to  a  stick.  Four  individuals  are  here  seen,  gracefully  en- 
twined together  in  various  attitudes  and  in  different  states  of  expansion.  In  the 
upper  figures,  the  distended  mouth  encircled  with  its  spiral  wreath  of  cilia  is 
fully  displayed,  and  numerous  cilia  are  likewise  seen  covering  the  surface  of  the 
body,  but  appearing  most  thickly  near  its  lower  extremity,  by  which  the  ani- 
malcule has  anchored  itself  to  the  sunken,  spray.  In  the  remainder  of  the  group 
the  mouths  of  the  animalcules  are  turned  from  view,  but  the  position  of  these 
orifices  is  marked  by  the  surrounding  crowns  of  oilia.  These  animalcules  are  of 
a  beautiful  green  hue,  and  vary  in  length  from  one-twenty-fourth  to  one-one  hun- 


44 


VIEWS    OF    THE    MICROSCOPIC    WORLD. 


Fig.  53. 


Fig.  55. 


Fig.  54. 


Fig.  56. 


dred  and  twentieth  of  an  inch, 
and  are  found  abundantly  in 
stagnant  water,  upon  decayed 
sticks,  stones,  and  leaves  ;  on  the 
surface  of  which  they  cluster  in 
countless  myriads.  The  appear- 
ance they  then  present  is  similar 
to  that  shown  in  figure  54,  which 
represents  a  twig  encased  in  a 
mass  of  green  jelly,  consisting 
of  thousands  of  animalcules  of 
this  kind.  The  twig  was  taken 
from  a  lake  by  Dr.  Mantell,  and 
was  part  of  a  branch  three  feet 
long,  that  had  fallen  into  the 
water  and  was  entirely  cover- 
ed with  the  congregated  mul- 
titudes of  these  Infusoria.  The 


Fig.  57. 


group  just  described  displays  the  animalcule  when  extended 
to  its  full  length  ;  but  in  swimming  it  contracts  into  the  shape 
of  a  cylindrical  cup  with  a  spiral  margin,  as  exhibited  in  figure 
55.  The  Blue  stentor  is  shown  in  figures  56  and  57. 
In  the  first  it  is  seen  elongated,  as  it  appears  when  attached 
to  some  object,  and  in  the  latter  under  the  shape  it  assumes 
when  swimming.  Its  voracity  is  plainly  evinced  by  the  num- 
ber of  animalcules  within  the  enclosure  of  its  funnel-shaped 
mouth,  below  which  the  rows  of  stomach-cells  are  apparent, 
extending  to  b.  This  species  has  a  crest  (c,  c,)  extending  along 
its  body.  The  length  of  the  creature  is  one-four  hundred  and 
eightieth  of  an  inch. 


INFUSORIAL    ANIMALCULES.  45 

PURSE  ANIMALCULE. — A  species  of  this  animalcule  is  represented  in  figure  58. 
Its  body,  which  is  white  and  round,  is  covered  with  cilia,  Fig.  58. 

arranged  in  circular  rows,  and  the  double  fringes  that  sur- 
round the  large  opening  which  constitutes  its  mouth  are 
longer  than  the  rest.  Its  stomachs,  which  resemble  in 
shape  small  purses,  are  not  connected  together  in  a  chain  ; 
but  are  attached  to  the  interior  of  the  animalcule,  by  slen- 
der stems.  These  Infusoria  are  found  with  the  dust-monad 
and  tablet-animalcules,  which  they  devour  in  great  num- 
bers, and  in  the  specimen  delineated,  several  of  these  crea- 
tures are  seen  within  its  body.  The  natural  length  of  this 
species  of  purse-animalcule  is  one-one  hundred  and  eighth 
of  an  inch. 


WHEEL-ANIMALCULES,  OR  ROTATORIA. 

These  interesting  animalcules,  of  which  there  is  a  great  variety,  constitute  one 
of  the  great  classes  into  which  the  Infusorial  world  is  divided.  They  live,  for 
the  most  part,  in  water  ;  but  it  does  not  appear  to  be  necessary  to  their  existence 
that  they  should  be  enveloped  by  this  fluid.  They  are  frequently  found  to  reside 
in  moist  earth,  and  some  species  are  known  to  dwell  in  the  cells  of  mosses  and 
sea-weed.  We  have  already  observed  that  these  Infusoria  have  received  their 
name  from  the  apparent  revolution  of  their  crowns  of  cilia,  and  that  in  addition 
to  this  marked  peculiarity,  they  are  distinguished  from  the  Polygastric  animal- 
cules by  possessing  a  single  stomach,  and  in  being  furnished,  for  the  most  part, 
with  jaws  and  teeth.  The  Rotatoria,  though  endowed  with  the  power  of  chang- 
ing the  shape  of  their  bodies,  by  contraction  and  expansion,  cannot  do  so  by  the 
growth  of  buds,  or  self-division,  like  many  kinds  of  the  first  class.  At  the  lower 
extremity  of  the  body  is  a  short  stem,  or  tail,  by  which  the  animalcule  fastens 
itself  to  some  fixed  object,  at  its  pleasure,  and  thus  prevents  the  upper  part  of 
the  body  from  partaking  of  the  motion  of  the  cilia.  This  class  of  Infusoria  are 
viviparous,*  and  also  multiply  from  eggs,  which,  in  some  species,  are  equal  in 
length  to  one-third  of  the  extent  of  the  body.  For  an  unknown  period  of  time, 
the  eggs  retain  the  living  principle  within  them,  exposed  to  heat  and  cold,  to 
moisture  and  to  drought :  they  are  borne  upon  the  wings  of  the  wind,  over  sea  and 
land,  bursting  into  life,  and  filling  the  water  with  their  swarming  multitudes, 
whenever  a  concurrence  of  circumstances  favorable  to  their  development  calls 
them  into  existence.  Nor  is  this  tenacity  of  life  confined  to  the  egg ;  the  ani- 
malcule itself,  as  we  have  previously  shown,  slumbers  for  months,  in  apparent 
death,  and  is  repeatedly  revived. 

THE  COMMON  WHEEL-ANIMALCULE. — This  species  of  Infusoria,  which  is  a 
very  interesting  subject  for  examination,  is  presented  to  view  in  figures  59,  60,  61, 
62,  63,  64,  and  65. 

*  Producing  young  in  a  living  state. 


46  VIEWS    OF    THE    MICROSCOPIC    WORLD. 

These  singular  creatures  are  found  in  the  red  sediment  left  in  gutters  and 
troughs,  after  the  rain-water  contained  in  them  has  evaporated  ;  also  in  vegetable 
infusions,  especially  that  of  hay ;  and  they  likewise  swarm  in  great  abundance  in 
ponds  covered  with  water-plants.  In  sea-water  they  are  also  detected,  and  it  is 
said  that  they  have  even  been  observed  moving  freely  in  the  cells  of  terrestrial 
and  marine  plants. 

The  wheel-animalcule  enjoys  the  sunshine,  and  can  seldom  be  taken  in  a  cloudy 
day ;  for  then  it  seeks  the  bottom  of  the  water,  lurking  around  the  roots  of 
the  weeds  that  grow  therein.  When  the  small  pools  in  which  they  reside  have 
been  reduced  by  evaporation,  they  become  so  numerous  as  to  tint  the  water  with 
a  bright  red.  They  have  then  attained  their  full  size,  and  the  richness  of  their 
hue  is  at  its  height ;  but  if  they  are  now  confined  in  a  vessel  for  a  few  days,  their 
color  fades  entirely  away.  Pritchard  remarks  that  he  had  found  wheel  animals, 
taken  under  the  circumstances  just  detailed,  to  measure  one-thirtieth  of  an  inch 
in  length  ;  while  those  raised  in  artificial  infusions  seldom  exceeded  half  that  size. 
They  were  so  numerous  that  thirty  were  contained  in  a  single  drop.  He  also 
observes,  that  they  are  easily  preserved  for  a  long  time,  by  occasionally  placing 
a  little  hay  in  the  water  of  the  glass  vessel  in  which  they  live.  He  was  enabled 
in  this  manner  to  keep  them  for  the  space  of  five  years ;  and  the  drawings  we 
shall  now  describe  are  representations  of  specimens  preserved.  The  wheel-ani- 
malcules are  mostly  seen  under  the  forms  delineated  in  figures  59  and  60 — the 
first  of  which  represents  a  full-grown  animalcule,  and  the  second  the  same  when 
young.  The  double  cup-shaped,  wheel-like  organs  are  seen  at  c?,  d,  in  figure  59,  sur- 
mounting the  head  of  the  creature,  and  are  each  furnished  with  circles  of  cilia, 
apparently  in  constant  rotation ;  causing  currents,  as  shown  by  the  arrows,  to 
set  towards  the  opening  between  the  wheel,  bearing  along  the  particles  of  matter 
upon  which  they  feed.  From  this  opening  the  food  is  carried  through  the  neck, 
m,  (the  position  of  which  is  indicated  by  a  dark  line)  to  the  mouth,  /,  situated 
at  the  bottom  of  the  neck.  These  curious  organs  are  more  clearly  displayed  in 
figure  7,  where  not  only  the  crowns  of  cilia,  but  the  jaws,  teeth,  and  eyes,  are  de- 
lineated as  they  appear  when  very  highly  magnified.  Here  the  rotatory  organs  are 
seen  consisting  each  of  twelve  or  fourteen  groups  of  cilia,  which,  swinging  round 
upon  their  bases,  describe  small  conical  surfaces,  terminated  by  the  dotted  circles. 
The  animalcule  is  endowed  with  the  power  of  changing  the  direction  in 
which  the  wheels  appear  to  revolve,  and  also  of  instantly  drawing  in  the  whole 
of  its  wheelwork.  The  head  then  assumes  the  form  presented  in  figure  61, 
where  it  is  terminated  by  a  cluster  of  hairs  that  do  not  revolve.  This  tuft  is  re- 
garded as  a  set  of  filaments  distinct  from  those  that  encircle  the  wheel-organs  ; 
and  which  are  supposed  to  perform  the  office  of  feelers,  as  they  are  usually  pro- 
truded when  the  animal  is  moving  from  place  to  place.  Near  the  head,  and  at 
the  upper  part  of  the  tube  through  which  the  creature  receives  its  food,  are  four 
muscular  masses  of  a  hemispherical  form,  placed  opposite  to  each  other,  as  shown 
in  figure  7.  Two  of  the  masses  are  furnished  with  jaws  and  teeth ;  the 
jaws  are  semi-circular  in  form,  and  are  each  armed  with  two  teeth,  that  are  in- 


^    , 


a» 


> 


INFUSORIAL    ANIMALCULES.  47 

serted  in  the  arched  portion  of  the  jaws.  These  organs  are  frequently  seen  in 
action,  when  the  creature  is  feeding,  and  are  distinguished  without  difficulty. 
Between  the  rotatory  organs  are  situated  the  eyes  of  the  animalcule,  which  are 
two  in  number,  and  of  a  red  hue.  For  certain  reasons,  Dr.  Ehrenberg  has  been 
led  to  suppose  that  these  eyes  are  not  simple,  but  complex,  like  those  of  insects ; 
each  organ  of  vision  consisting  of  a  number  of  lenses,  which  form  as  many  sep- 
arate images  of  a  single  object  before  them.  There  is  also  a  tube  projecting  from 
the  neck,  the  position  of  which  is  indicated  at  b,  in  figure  61  ;  through  this, 
water  flows  into  the  body  of  the  creature,  for  the  purpose  of  affording  constant 
supplies  of  air.  The  wheel-animalcule  moves  through  the  water  by  two  differ- 
ent methods.  The  first  is  by  swimming  which  is  accomplished  by  the  rotatory 
action  of  its  crowns  of  cilia ;  and  in  the  second  method  the  tail  is  employed. 
This  member  is  provided  with  two  pairs  of  projections,  g  g,  figure  59,  which  may 
be  termed  feet,  and  is  likewise  divided  at  the  end.  By  alternately  attaching  its 
head  and  tail  to  the  surface  ot'  the  object  upon  which  it  moves,  the  animalcule 
advances  in  its  course,  bending  itself  upward  in  the  manner  of  a  caterpillar,  in 
order  to  effect  this  object.  Wheel-animals  progressing  in  this  way  are  delineated 
in  figures  62  and  63.  In  the  various  figures  presented,  we  perceive  joints  and 
rings,  like  those  which  surround  the  common  worm.  The  joints  are  not  limited 
in  number,  nor  confined  to  any  particular  situation  on  the  body  of  the  animal- 
cule, and  where  any  joint  occurs  the  smaller  parts  slide  in  and  out  of  the  larger, 
like  the  tubes  of  a  telescope.  From  this  peculiarity  these  Infusoria  can  assume 
the  form  of  a  sphere,  the  head  and  tail  being  drawn  within  the  body.  This 
movement  is  nearly  effected  in  figure  64,  the  toes  being  still  attached  to  a  stem. 
In  figure  65  the  animalcule  is  entirely  contracted,  and  forms  a  spherical  ball.  A 
number  of  the  eggs  of  the  wheel-animalcule  are  shown  below  figure  59. 
In  form  they  are  oval,  with  a  richly  granulated  surface.  They  vary 
in  color,  being  sometimes  of  a  delicate  pink,  and  at  others  of  a  deep  golden 
yellow. 

THE  CROWN  WHEEL-ANIMALCULE,  OR  STEPHANOCEROS. — This  elegant  little 
creature  has  received  the  name  of  Stephanoceros,  from  the  Greek  word  Stephanos, 
a  crown.  It  is  found  in  ponds,  amid  the  leaves  of  aquatic  plants,  and  usually 
measures  one  thirty-sixth  of  an  inch  in  length.  A  specimen  of  these  Infusoria, 
which  was  carefully  studied  and  delineated  by  Dr.  Mantell,  is  represented  in 
figure  66,  and  displays  at  a  glance  its  singular  peculiarities  of  structure. 
The  Stephanoceros  is  here  beheld  fully  extended,  enclosed  in  a  transparent, 
cylindrical  case,  a  a,  which  is  flexible  in  its  nature,  and  is  attached  to  the 
body  of  the  animalcule,  near  the  head,  as  seen  at  c.  The  head  is  adorned  with 
a  crown,  consisting  of  five  long  branching  arms,  d  d  d  d  d,  each  of  which  is 
fringed  with  fifteen  small  circles  of  cilia,  that  are  perpetually  vibrating.  Upon 
the  currents  produced  by  the  motion  of  the  cilia,  the  prey  of  the  Stephanoceros 
floats,  till  it  comes  within  its  grasp,  when  it  is  seized  by  the  long  arms  of  the 
creature,  and  firmly  held  until  it  is  devoured.  In  the  figure  several  animalcules 


48 


VIEWS    OF    THE     MICROSCOPIC    WORLD, 


Fig.  66. 


Fig.  67. 


are  seen  which  have  thus  been  captured  and  swallowed :  it  is  likewise 
by  means  of  these  fringed  arms  that  locomotion  is  effected.  In  figure  67,  the 
Stephanoceros  is  seen  drawn  within  its  case.  This  change  of  attitude  it  effects 
instantaneously,  upon  the  slightest  alarm :  the  arms  are  then  closed  together, 
and  the  case  contracts  in  wrinkles ;  the  upper  edge  being  drawn  inward,  as 
the  part  of  the  animalcule  to  which  it  is  united  sinks  down  toward  the  bottom 
of  its  crystal  cell.  The  tube  is  thus  doubled  inward  upon  itself,  like  the  finger 
of  a  glove  turned  partially  outside  in. 

The  Stephanoceros  is  said  to  possess  a  single,  small,  red  eye,  which  is  not  seen 


INFUSORIAL    ANIMALCULES.  49 

in  these  figures.  The  minute  circles  at  c  represent  several  fleshy  masses,  which 
are  arranged  two  and  two  at  the  base  of  each  arm,  and  are  supposed  to  be 
centres  of  the  nervous  matter  provided  for  each  member.  The  position  of  the 
mouth  is  indicated  by  the  letter/,  and  below  it,  at  g,  is  the  stomach,  which  is 
comparatively  large,  and  is  here  exhibited  filled  with  many  of  the  smaller 
Infusoria.  The  jaws  of  the  Stephanoceros  are  furnished  with  teeth,  with  which 
it  is  seen  to  tear  and  masticate  its  food.  Two  distinct  sets  have  been  discovered 
on  each  jaw;  of  which,  in  their  natural  position,  figure  68  is 
a  highly  magnified  representation.  The  lower  set  is  seen  at 
a,  and  the  upper  at  b  ;  the  latter  appear  to  consist  of  two  on 
each  side  ;  but  they  are  not  all  seen  in  the  figure,  for  the 
actual  number  is  eight,  four  upon  either  jaw.  So  fierce  and 
voracious  is  the  crowned  animalcule,  that  it  attacks  and  seizes 
the  Stentor  with  its  long  and  flexible  arms. 

The  Stephanoceros  increases  by  eggs,  which  are  hatched  before  they  pass 
from  the  animalcule  into  the  cavity  of  its  transparent  case.  The  progressive 
development  of  the  young,  during  the  first  stages  of  their  existence,  has  been 
studied  by  Dr.  Mantell  with  the  most  patient  assiduity.  This  gentleman  observed 
that  the  young  Stephanoceros,  three  hours  after  it  had  escaped  from  the  egg, 
swam  freely  in  the  surrounding  water ;  in  thirty  hours  a  group  of  five  buds 
were  beheld,  which  were  regarded  as  the  bases  of  the  five  branching  arms  con- 
stituting the  crown ;  in  eighty  hours  they  were  fringed  with  cilia,  and  the 
position  of  the  stomach  was  detected  by  the  color  of  the  food  which  the  young 
animalcule  had  swallowed. 

The  specimens  of  the  crowned  animalcule,  which  are  represented  in  the  above 
figures,  belong  to  a  species  obtained  by  Dr.  Mantell  from  a  lake  in  the  vicinity 
of  London.  A  supply  of  them  was  kept  without  any  difficulty  in  glass  jars  of 
water,  containing  aquatic  plants,  during  the  residence  of  this  gentleman  at 
Clapham.  But  upon  removing  to  another  place,  these  interesting  creatures 
died,  although  they  were  furnished  with  their  native  water,  and  every  precaution 
was  taken  to  ensure  their  lives.  This  mortality  is  attributed  by  Dr.  Mantell  to 
a  difference  in  the  local  influence  of  the  atmosphere. 

THE  BEADED  MELICERTA,  OR  FOUR-LEAVED  ANIMALCULE. — This  minute  crea- 
ture, which  is  delineated  in  figures  69,  71,  and  72,  belongs  to  the  same  family  of 
Infusoria  as  the  Stephanoceros.  It  possesses,  when  young,  two  eyes,  a  tubular  case, 
and  a  single  rotatory  organ,  which,  when  expanded,  presents  the  appearance  of 
four  leaves,  fringed  with  numerous  cilia,  as  shown  in  the  figure.  Below  this 
complex  apparatus  the  mouth  is  situated,  the  jaws  of  which  are  armed  with 
rows  of  teeth,  which  are  discerned  in  figure  69,  near  the  centre  of  the  leaves ; 
but  are  exhibited  more  highly  magnified  in  figure  70.  This  animalcule  has  been 
found  to  be  endowed  with  a  nervous  system ;  and  two  tubes  are  situated  near  the 
neck  that  apparently  subserve  the  purpose  of  respiration. 

The  body  of  the  Melicerta  is  transparent,  but  the  enclosing  cell  is  of  a  brown- 

4 


50 


VIEWS    OF    THE     MICROSCOPIC    WORLD. 
Fig.  70.  Fig.  69. 


Fig.  71. 


Fig.  72. 


ish  hue,  somewhat  conical  in  shape ;  and  its  surface  is  composed  of  a  numerous 
collection  of  small,  regularly  formed  bodies,  like  beads ;  from  which  resemblance 
this  species  of  Melicerta  derives  its  name.  These  bodies  are  arranged  in  circular 
rows,  as  seen  in  the  figures,  and  present  a  very  beautiful  appearance.  The  en- 
closing case  in  the  young  Melicerta  is  at  first  clear  and  pellucid  like  crystal ;  but 
as  it  gradually  enlarges  rings  of  beads  commence  forming  around  it,  until  at 
last  the  whole  surface  becomes  entirely  covered  with  them. 

The  appearance  of  the  Melicerta,  at  an  early  stage  of  its  existence,  is  exhibited  in 
figure  71,  where  the  tubes  of  respiration  are  shown  at  aa ;  the  delicate  transpa- 
rent case  at  b  b  ;  and  the  first  formed  circles  of  beads  at  c  c.  The  bead-shaped 
bodies  are  deposited  by  the  animalcule  itself,  and  are  cemented  together  by  a 
glutinous  matter  which  exudes  from  its  body  and  hardens  by  exposure  to  water. 


INFUSORIAL    ANIMALCULES. 


51 


The  surrounding  shell  of  the  Melicerta  is  inflexible,  and  the  soft  and  tender 
animalcule  can  withdraw  itself  at  pleasure  within  its  protecting  envelope.  The 
creature  is  exceedingly  sensitive,  and  shrinks  into  the  concealment  of  its  case 
upon  the  slightest  motion  of  the  water  in  which  it  lives.  It  is  seen  partially 
withdrawn  in  figure  72,  where  the  rotatory  organs  are  seen  closed  up,  and  the 
two  eye-specks  are  detected  at  a  a.  The  Melicerta  is  found  upon  the  leaves  of 
duckweed  and  other  water  plants.  Its  size,  when  expanded,  is  one-twelfth  of  an 
inch ;  the  length  of  the  case  one  twenty-fourth  ;  and  that  of  the  eggs  are  one- 
one  hundred  and  fiftieth  of  an  inch. 

Fig.  73. 


52  VIEWS    OF    THE    MICROSCOPIC    WORLD. 

THE  HORN  WORT  LIMNIAS,  or  WATER  NYMPH. — This  animalcule,  like  the  one 
immediately  preceding,  is  enclosed  in  a  cylindrical  case,  which,  at  first,  is  white 
and  transparent ;  but  afterwards  assumes  a  brownish  hue.  The  matter  com- 
posing the  case  is  glutinous,  and  extraneous  particles  often  form  a  coating  upon 
its  smooth  surface.  Unlike  the  Melicerta,  its  rotatory  organ  is  divided  into  two 
leaves  only,  fringed  with  vibrating  cilia. 

The  Limnias  has  two  red  eyes,  which  can  only  be  discerned  when  the  animal- 
cule is  very  young.  These  organs,  together  with  the  jaws,  may  be  seen 
in  the  Limnias  in  the  egg,  before  it  has  burst  the  transparent  shell.  In 
figure  73,  a  group  of  these  interesting  Infusoria  are  delineated  as  they  ap- 
pear attached  to  a  stem  of  horn  wort ;  a  plant  of  which  they  are  so  fond  that  they 
have  been  designated  by  its  name.  The  several  individuals  are  here  seen  more 
or  less  protruded  from  their  cases  ;  for,  like  the  rest  of  the  flower-wheel  animal- 
cules, to  which  they  belong,  they  are  endowed  with  the  power  of  extending 
themselves  beyond  the  margin  of  their  cases,  and  of  shrinking  completely  within 
them.  The  parent  animalcule  (  a  )  has  its  wheelwork  fully  protruded  ;  its  jaws 
and  teeth  are  apparent  at  6,  and  within  the  sheath  a  row  of  eggs  (cccc)  are  visible. 
In  figure  74,  a  young  Limnias  is  represented  as  it  appears  when  just  es-  Fie-  74- 
caped  from  the  egg  ;  in  this  minute  specimen  the  jaws  and  teeth,  and 
the  two  red  eye-specks  are  clearly  perceived  at  a  and  b.  The  length  of  the 
Limnias  is  about  one-twentieth  of  an  inch,  and  that  of  the  case  one  half 
the  size  of  the  animalcule. 

THE  ELEGANT  FLOWER-SHAPED  ANIMALCULE. — Another  type  of  the  flower- 
shaped  animalcule,  and  which,  from  its  beauty,  has  received  the  above  name, 
is  represented  in  figures  75  and  76,  upon  the  stem  of  a  water-plant.  It  is 
enclosed  in  a  delicate  and  flexible  crystalline  case  (a)  and  its  rotary  organ  is 
divided  into  six  leaves,  (b  b)  from  the  ends  of  which  brushes,  formed  of  very 
long  filaments,  project.  This  creature  is  capable  of  expanding  and  contracting 
itself  to  a  very  great  extent ;  for  at  one  time  it  can  thrust  out  nearly  the  whole 
of  its  body  beyond  its  sheath,  as  seen  in  figure  75  ;  and  at  another  conceal 
itself  completely  within,  leaving  nothing  but  the  long  cilia  projecting  without, 
as  displayed  m  figure  76.  In  extending  itself,  the  flower-shaped  animalcule 
moves  slowly ;  but  its  contraction  is  quickly  performed  ;  and  in  effecting  this 
change  in  its  shape,  the  animalcule  not  only  shortens  its  body,  but  also  the  flex- 
ible case,  which  gathers  down  upon  itself  in  circular  folds.  They  are  very  vora- 
cious creatures,  feeding  upon  great  numbers  of  monads,  and  the  little  ship- 
animalcules,  which  can  often  be  distinctly  seen  within  the  stomach,  as  shown  at 
c.  The  position  of  the  jaws  and  teeth,  with  which  they  crush  and  tear  their  prey, 
is  indicated  by  the  letter  e  ;  and  their  structure  and  arrangement  are  apparent 
in  figure  77,  which  represents  this  formidable  apparatus  very  highly  magnified. 
In  figure  76,  a  young  animalcule,  with  its  two  eyes,  is  seen  at/,  in  the  envelope 
containing  the  eggs  of  the  parent.  The  size  of  the  Flower-shaped  animalcule 
is  about  the  one-one  hundred  and  eighth  part  of  an  inch. 


INFUSORIAL    ANIMALCULES. 
Fig.  75. 


Fig.  77. 


54  VIEWS    OF    THE    MICROSCOPIC    WORLD. 


CHAPTER  II. 

FOSSIL     INFUSORIA. 

"  All  that  tread 

The  globe,  are  but  a  handful,  to  the  tribes 
That  slumber  in  its  bosom." — Bryant 

"  "Where  is  the  dust  that  has  not  been  alive  ?"—  Young. 

WHEN  the  loricated  Infusoria  die,  their  soft  and  gelatinous  parts  quickly 
decompose  ;  but  their  shells  or  cases  remain,  retaining  for  ages  their  peculiar 
forms  and  structures.  To  such  an  extent  do  these  minute  beings,  swarming 
throughout  the  waters  of  the  globe,  increase,  by  their  various  modes  of  produc- 
tion ;  and  so  rapidly  do  these  myriad  generations  succeed  each  other,  that  the 
shells  of  Infusoria,  which  perished  centuries  ago  are  now  found  in  a  fossil  state, 
constituting  a  large  proportion  of  the  materials  of  extensive  tracts  of  land,  several 
feet  in  thickness,  that  cover  the  surface  of  the  earth  for  many  miles.  These 
cases  consist,  for  the  most  part,  of  lime,  iron,  and  flint,  and  entire  ranges  of  hills 
and  masses  of  rock  are  composed  of  these  minute  envelopes.  Dr.  Ehrenberg  has 
ascertained,  that  no  less  than  five  kinds  of  rocks  and  mineral  substances  consist 
wholly  or  in  part,  of  the  fossil  shells  of  Infusoria,  and  that  three  other  kinds  have 
probably  the  same  origin.  Bog  iron  is  made  up  of  microscopic  iron  shells,  and 
the  remains  of  animalcules  have  been  abundantly  discovered  in  beds  of  marl.  So 
numerous  are  these  fossil  coverings  amid  the  chalk  cliffs,  that  they  are  detected 
in  the  smallest  portion  of  chalk  that  can  be  taken  up  on  the  point  of  a  knife. 
The  deposites  at  the  mouth  of  rivers  frequently  consist,  to  a  large  extent,  of  Infu- 
soria, both  living  and  fossil ;  and  the  land  is  thus,  in  many  places,  continually 
advancing  upon  the  sea,  from  a  cause  which,  until  a  few  years  ago,  had  entirely 
escaped  observation. 

The  searching  investigations  'of  distinguished  naturalists  have  furnished  a  most 
interesting  fund  of  facts,  which  fully  attest  the  truth  of  the  above  remarks.  In 
Bilin,  in  Bohemia,  a  mass  of  slate  has  been  discovered,  forming  a  series  of  strata 
fourteen  feet  thick,  almost  entirely  composed  of  the  flinty  shells  of  Infusoria.  It 
is  used,  when  ground,  as  a  polishing  powder,  under  the  name  of  tripoli.  A  sin- 
gle druggist's  shop  in  Berlin  disposes,  yearly,  of  more  than  twenty  hundred 
weight,  and  the  supply  is  still  sufficient  for  the  demands  of  trade.  The  smallest 
quantity  of  this  powder,  when  examined  by  the  microscope,  is  seen  to  be  full  of 
the  fossil  remains  of  animalcules,  as  is  likewise  true  of  tripoli  from  other  locali- 
ties. A  cubic  inch  of  the  Bilin  stone  weighs  two  hundred  and  twenty  grains, 
and  contains  no  less  than  (40,000,000,000)  forty  thousand  millions  of  distinct, 
organic  forms.  The  species  of  Infusoria  of  which  nearly  the  whole  mass  is  com- 
pacted, is  the  divided  Gallionella,  or  box-chain  animalcules  ;  a  kind  of  Infusoria 
which  has  already  been  described.  A  specimen  from  this  slate  is  delineated  JM 


FOSSIL     INFUSORIA. 


55 


Fig.  79. 


figure  78,  magnified  three  hundred  times.     Its  natural  length   does  not  exceed 
one-sixth  of  the  thickness  of  a  human  hair,  and  the  flinty  shell  Fj(r  ?8 

of  a  single  animalcule  weighs  only  the  one  hundred  and  eighty  - 
seven  millionth  part  of  a  grain.  The  identity  of  the  fossil  and 
living  animalcules  is  seen  at  a  glance  by  comparing  the  engra- 
vings in  which  they  are  respectively  represented.  In  Virginia,  extensive  beds  of 
flinty  marls  have  been  discovered  by  Prof.  Rogers,  composed,  in  a  great  measure,  of 
the  shells  of  different  species  of  marine  animalcules.  The  towns  of  Richmond  and 
Petersburg  are  built  upon  these  strata,  which  vary  in  thickness  from  twelve  to  twen- 
ty-five feet,  and  comprise  tracts  and  districts  of  considerable  extent.  So  full  is  this 
earth  of  microscopic  fossil  remains,  that  when  a  little  of  it  has  been  mixed  with  a 
drop  of  water,  and  the  liquid  has  evaporated  from  the  glass  slide,  the  smallest 
stain  left  upon  the  surface  abounds  with  curious  Infusorial  structures,  whose  living 
types  inhabit,  to  a  great  extent,  the  neighboring  seas. 

In  figure  79,  are  shown  two  species  of  Navicula,  which,  with 
several  others,  have  been  recognised  in  the  Richmond  earth ;  but 
the  most  exquisite  structure  here  revealed  is  a  beautiful,  saucer- 
shaped  shell,  the  surface  of  which  is  divided  into  hexagonal  or  six- 
sided  figures,  like  the  cells  of  a  honey-comb.  The  animalcule  to 
which  it  belongs  is  called,  from  the  appearance  of  its  shell,  the 
Coscinodiscus*  or  sieve-like  disk :  there  are  several  species  of  these 
Infusoria,  whose  shells  vary  in  size  from  one-hundredth  to  one-thou- 
sandth of  an  inch  in  diameter. 

In  figure  80,  is  displayed  a  portion  of  the  circular  shell  of  an  elegant  species 
found  in  the  Virginia  marl,  which  has  received  the  name  of  Fig  80 

the  Radiated  coscinodiscus.  It  is  shown  very  highly  magnified, 
and  the  rich  and  perfect  arrangement  of  symmetrical  forms 
here  exhibited,  is  but  a  faithful  copy  of  the  wondrous  original. 
These  beautiful  fossil  shells  are  not  confined  to  the  Richmond 
locality,  but  have  been  discovered  in  the  chalk  marls  of  Zante  and 
Gran  ;  and  Col.  Fremont  likewise  found  them  in  Oregon,  at  the 
Riviere  Aux  Chuttes.  The  various  species  of  this  animalcule 
exist  in  a  living  state  in  the  sea  near  Cuxhaven,  at  the  mouth 
of  the  Elbe  ;  and  the  Radiated  coscinodiscus  has  also  been  de- 
tected in  the  waters  of  the  Baltic,  near  Wismar. 

A  like  deposit  of  Infusorial  shells,  fifteen  feet  thick,  exists  at  An- 
dover,  Ct,  and  Ehrenberg  remarks,  in  his  memoir  on  the  Micro- 
scopic life  of  North  and  South  America,  "  that  similar  beds  oc- 
cur by  the  river  Amazon,  and  in  great  extent  from  Virginia 
to  Labrador." 

In  Sweden  and  Lapland,  a  white,  mealy  earth  is  found  distributed  in  layers, 
sometimes  thirty  feet  in  thickness.     It  is  wholly  composed  of .  the  shells  of  ani- 

*  From  kosMnon,  (Greek)  a  sieve. 


56  VIEWS    OF    THE    MICROSCOPIC    WORLD. 

malcules,  and  when  mixed  with  the  ground  bark  of  trees  is  used  by  the  inhabi- 
tants as  an  article  of  food  in  times  of  scarcity.  The  same  kind  of  earth  occurs 
in  San  Flora  in  Tuscany,  and  also  near  Egra  in  Bohemia,  about  three  feet  below 
the  surface  of  the  ground.  To  the  eye  it  appears  when  dry  like  pure  magnesia ; 
but  when  examined  by  the  microscope,  it  is  seen  to  consist  entirely  of  a  richly 
figured  species  of  Infusorial  shell,  which  is  called  the  Campilodiscus.  A  specimen 
Fig.  si.  fr°m  tms  locality,  very  highly  magnified,  is  delineated  in  figure  81. 
Its  natural  size  varies  from  one-four  hundred  and  thirtieth  to 
one-two  hundred  and  fortieth  of  an  inch.  In  the  province  of 
Luneberg,  in  Saxony,  a  layer  of  eatable  Infusorial  earth  also 
occurs,  twenty-eight  feet  in  thickness,  which  is  the  greatest  deposit 
that  has  yet  been  discovered  :  and  similar  strata  have  been  found 
in  Africa,  Asia,  and  the  South  Sea  Islands.  On  the  banks  of  the  Amazon,  in 
South  America,  an  Infusorial  clay  occurs  of  the  same  nature.  It  is  not  a  recent 
deposit  from  the  swelling  of  the  river ;  but  is  an  ancient  bed  whose  age  is  unde- 
termined, and  exists  as  an  elevated  and  extensive  plain,  shaded  with  woods  and 
the  thick  foliage  of  forests. 

FOSSIL  ANIMALCULES  OF  CHALK  AND  FLINT. — Chalk  consists  in  a  great 
measure  of  fossil  Infusoria,  together  with  minute  shells,  so  exceedingly  small  that 
a  million  distinct  structures  are  computed  by  Ehrenberg  to  be  contained  in  the 
space  of  a  cubic  inch.  These  organic  remains  constitute  nearly  half  the  bulk  of 
the  chalk  of  Northern  Europe,  and  exceed  this  proportion  in  that  of  Southern 
Europe.  The  portion  of  these  chalk  formations  that  is  not  organized  was  origi- 
nally shells,  which  having  become  decomposed,  now  form  a  cement  for  the  organic 
remains,  uniting  them  together  in  one  compact,  mass.  The  larger  shells  are  per- 
ceived, when  the  sediment  obtained  by  brushing  chalk  into  water  is  closely  ex- 
amined ;  but  in  order  to  detect  the  true  microscopic  structures,  the  following  pro- 
cess must  be  adopted,  which  has  been  pursued  by  Ehrenberg.  A  drop  of  water 
is  first  placed  upon  a  thin  slip  of  glass,  and  then  upon  the  water  as  much  scraped 
chalk  must  be  spread  as  will  cover  the  fine  point  of  a  knife.  After  leaving  the 
chalk  to  rest  for  a  few  seconds,  the  finest  particles  suspended  in  the  water  must 
be  withdrawn,  together  with  most  of  the  liquid ;  and  the  remainder  suffered  to 
become  perfectly  dry.  This  sediment  must  now  be  covered  with  Canadian  bal-' 
sam,  and  the  glass  held  over  a  spirit  lamp  until  the  balsam  becomes  slightly  fluid 
without  froth  or  air  bubbles.  In  this  state  it  is  kept  for  a  short  time,  until  the 
balsam  thoroughly  penetrates  every  part  of  the  sediment,  flowing  into  the  cham- 
bers and  cavities  of  the  microscopic  shells,  and  causing  their  structure  to  be 
more  readily  detected.  When  a  preparation  thus  made  is  magnified  three  hun- 
dred times,  the  chalk  is  seen  teeming  with  minute  organic  forms,  the  peculiarities 
of  which  are  so  clearly  revealed,  that  the  observer  is  enabled  to  arrange  and 
classify  them  with  the  utmost  ease.  Flint  to  a  large  extent  has  also  been  proved  to 
be  of  animal  orgin  ;  and  a  distinguished  English  naturalist  has  observed,  that 
masses  of  flint,  or  nodules  as  they  are  termed,  are  almost  entirely  composed  of 


FOSSIL   INFUSORIA. 


the  flinty  shells  of  animalcules,  mingled  with  the  scales  of  fishes,  zoophytes,  and 
the  remains  of  numerous  minute  animals.  The  microscopic  animal  structures 
that  abound  most  in  the  chalk  and  flint  of  England  are  two  kinds  of  Polythala- 
inia,*  or  many-chambered  shells ;  termed  the  Rotalia,f  or  wheel-shaped  animal- 
cule, and  the  Textularia,J  or  entwined  animalcule.  With  these  are  combined 
vast  numbers  of  minute  shells,  belonging  to  an  extensive  class  of  small  animals, 
which,  on  account  of  their  being  covered  with  pores, 'have  received  the  name  of 
Foraminifera.§ 

The  shells  of  the  Foraminifera  differ  in  their  dimensions.  Some  of  them  are 
perfectly  microscopic,  being  invisible  to  the  naked  eye ;  while  others  are  of  the 
size  and  shape  of  a  dollar ;  and  from  their  resemblance  to  a  coin  have  received 
the  name  of  N"ummulites,||  or  fossil-money. 

In  figures  82  and  83  are  delin-        Fig.  82.  Fig.  83.  Fig.  84. 

eated  two  microscopic  shells  of  the 
Rotalia,  each  of  which  is  seen  to( 
consist  of  several  compartments,  like 
that  of  the  nautilus;  though  they  are 
distinct  from  the  latter  in  their  nature. 
The  specimens,  from  which  the  ori- 
ginal drawings  were  taken,  were  discovered  in  the  chalk  and  flint  of  Surrey. 
Figure  84  represents  a  portion  of  a  nautilus  found  in  a  piece  of  Irish  flint;  five 
chambers  of  the  shell  are  clearly  seen,  partially  separated  from  each  other. 
The  three  figures  here  presented  are  all  very  highly  magnified. 

A  beautiful  species  of  microscopic  fossil,  that  is  likewise  found  in  chalk,  is  the 
Crosier-like  shell,  which  in  its  advanced  state  changes  its  original  shape,  and  as- 
sumes the  graceful  form  shown  in  figure  85,  which  presents  a  side  view  of  the 
object.  This  fossil  was  found  at  Chichester,  by  Mr.  Walter  Mantell,  and  is  here 
shown  as  it  appeared  when  magnified  eight  times. 


Fig.  85. 


Fig.  86. 


Fig.  87. 


Another  kind  of  the  microscopic  many-chambered  shells  is  the  Fan-shaped  an- 

*  From  polus,  (Greek,)  many,  and  thalamos,  (Latin,)  a  chamber. 

f  From  rota,  (Latin,)  a  wheel. 

\  From  textura,  (Latin,)  woven-work. 

§  From  foramen,  (Latin,)  opening,  and  ferre,  (Latin,)  to  bear. 

\  From  nummusy  (Latin,)  a  coin,  and  lithos,  (Greek,)  a  stone. 


58 


VIEWS    OF    THE    MICROSCOPIC    WORLD. 


Fig.  88. 


imalcule,  which  occurs  abundantly  in  the  chalks  of  France,  and  is  also  found  in 
those  of  England.  A  profile  of  this  shell,  magnified  twelve  times,  arid  bearing 
some  resemblance  to  a  fan,  is  shown  in  figure  86.  When  a  side  view  is  taken, 
and  the  fossil  is  highly  magnified,  the  beauty  of  the  structure  becomes  more  ap- 
parent, and  the  fluted  projections,  d  d,  are  revealed  as  elegant  spiral  shells, 
divided  into  several  apartments,  and  presenting  an  appearance  similar  to  that 
which  is  exhibited  in  figure  87. 

The  Textularia  or  entwined  animalcule  has  the  figure  of  a  cluster 
of  globes,  rising  in  the  form  of  a  pyramid,  and  when  a  section  is  made 
in  the  direction  of  its  length,  it  displays  the  different  cells  into  which 
the  cavity  of  the  shell  is  divided.     In  figure  88  is  shown  a  specimen 
from  the  marl  of  the  Mount  of  Olives,  and  an  outline  of  the  Ameri- 
can entwined  animalcule  is  exhibited  in  figure  89.      This  species  dif- 
fers in  some  respects  from  other  Textularia,  being  wholly  local  and  pe- 
culiar to  the  chalk  marls  of  the  Upper  Missouri ;  of  which  vast 
deposit  it  forms  the  principal  part.     The  living  Xanthidia,  or 
Cross-bar  animalcules,  have  already  been  described ;  and  in 
figures  90,  91,  92  and  93  are  presented  several  specimens  as 
they  appear  in  flint.     In  this  stone  they  often  occur  in  great 
abundance,  no  less  than  twenty  being  once  discovered  by  Mr. 
Hamlin  Lee,  in  a  chip  of  flint,  the  surface  of  which  was 
scarcely  the  twelfth  of  an  inch  in  diameter.     These  Infusoria 
are  easily  detected  in  flints  which  are  translucent ;.  the  only 
preparation  required  being  simply  to  select  the  thinnest  and 
clearest  flakes,  struck  off  by  the  blow  of  a  hammer,  and  before 
Viewing  them  with  a  microscope,  to  immerse  them  in  oil  of  tur- 
pentine, in  order  to  render  them  more  transparent.     The  specimens  of  Xanthi- 
dia represented  in  figures  90,  91,  92  and  93,  were  taken  from  a  remarkable 


Fig.  90. 


Fig.  91. 


Fig.  92. 


Fig.  93. 


group,  described  by  Dr.  Mantell,  and  found  by  his  son  in  a  flake  of  flint.  This 
flake  is  delineated  of  its  natural  size  in  figure  90  ;  in  figure  91  it  is  considerably 
magnified,  and  the  several  fossils  are  distinctly  seen.  Figures  92  and  93  are 
two  of  the  specimens  very  highly  magnified,  and  are  a  variety  of  the  Branched 
Xanthidium,  which  is  found  only  in  a  fossil  state.  That  they  belong  to  the  race 
of  the  Xanthidia  is  evident  from  the  resemblance  they  bear  to  the  drawings  of  the 
living  specimens,  figures  40  and  41.  Five  specimens  were  found  in  this  fragment  of 


FOSSIL    INFUSORIA. 


59 


flint,  varying  in  diameter  from  one-three  hundredth  to   one-Jive  hundredth  of  an 
inch. 

PEAT  BOGS. — The  peat  bogs  both  of  ancient  and  modern  origin,  are  frequently 
found  to  contain  beds  and  layers  of  a  white  flinty  earth,  which  is  entirely  com- 
posed of  the  shells  of  animalcules.  In  many  swamps  of  Ireland  and  England, 
earthy  strata  of  this  peculiar  nature  have  been  found ;  and  in  this  country,  Prof. 
Bailey  has  discovered  near  West  Point  a  deposit  eight  or  ten  inches  thick,  and 
in  all  probability  several  hundred  yards  in  extent,  wholly  made  up  of  the  flinty 
shells  of  the  Bacillaria  or  stick-animalcules,  in  a  fossil  state.  "  This  deposit," 
says  Prof.  B.,  "  is  about  a  foot  below  the  surface  of  a  small  peat  bog,  imme- 
diately at  the  foot  of  the  southern  escarpement  of  the  hill  on  which  the  celebra- 
ted Fort  Putnam  stands.  In  draining  this  bog  a  large  ditch  was  dug,  and  among 
the  matter  thrown  out,  my  attention  was  attracted  by  a  very  light  white  or  clay 
colored  substance,  which,  when  examined  closely  in  the  sunshine,  showed  min- 
ute, glimmering,  linear  particles.  On  submitting  it  to  observation,  by  means  of 
a  good  microscope,  I  found  it  to  be  almost  entirely  composed  of  fossil  Infusoria. 
There  can  be  no  doubt,  that  in  this  place  there  are  several  tons  of  the  shells  of 
beings  so  minute  as  to  be  barely  visible  as  brilliant  specks,  when  carefully  ob- 
served in  a  strong  light  by  the  naked  eye.  Hun- 
dreds of  years  must  have  elapsed  before  such 
an  accumulation  could  have  been  made."  The 
kind  of  shell  that  is  most  abundant  in  this 
earth  is  delineated  in  figure  94,  which  repre- 
sents a  specimen  magnified  three  hundred 
and  fifty  times ;  and  in  figure  95  is  shown 
the  appearance  presented  by  a  little  of  the 
earth  diffused  in  a  drop  of  water,  and  mag- 
nified about  fifty  times.  The  earth  is  here 
seen  consisting  of  a  great  number  of  shells 

of  various  shapes  and  sizes,  clearly  proving,  that  the  deposit  is  no- 
thing more  than  a  vast  assemblage  of  immense  multitudes  of  minute 
fossil  structures. 


Fig.  95. 


Fig.  94. 


FORAMINIFERA. — The  fossil  shells  of  these  minute  forms  of  animal  life  now 
exist  in  such  profusion,  rising  into  mountains,  and  extending  in  broad  and  deep 
layers  beneath  the  surface  of  the  earth,  that  it  has  been  observed  by  the  learned 
Dr.  Buckland,  "that  the  remains  of  such  .minute  animals  have  added  much 
more  to  the  mass  of  materials,  which  compose  the  exterior  crust  of  the  globe, 
than  the  bone  of  elephants,  hippopotami,  and  whales." 

In  these  vast  collections  the  Nummulites  largely  prevail.  They  are  divided 
into  numerous  species,  varying  in  dimensions  from  the  size  of  a  crown-piece  to 
that  of  a  grain  of  sand.  The  spiral  shell  of  the  nummulite  is  delineated  in 


60  VIEWS    OF    THE    MICROSCOPIC    WORLD. 

Fi  96  %ure  96  :  it  is  separated  into  a  very  great  number  of  small  cells  of 
nearly  equal  extent,  which  communicate  with  each  other  by  an  opening 
through  the  partitions  of  the  several  chambers.  It  is  supposed  that 
leach  cell  once  contained  a  distinct  animal,  and  that  the  entire  shell 
formed  the  common  habitation  of  a  vast  multitude.  The  chalk  formation 
at  Bayonne  and  of  the  Pyrenees,  consists  of  beds  of  crystalline  marble,  com- 
posed of  nummulites,  and  the  vast  limestone  range  at  the  head  of  the  Adriatic 
Gulf,  is  also  constituted  of  nummulites,  having  the  shape  and  size  of  a  small  pea. 
At  Suggsville,  in  the  United  States,  is  a  chain  of  mountains  three  hundred  feet 
high,  entirely  made  up  of  a  single  species  of  this  fossil.  The  great  pyra- 
mid of  Egypt,  which  covers  eleven  acres  of  ground,  and  rises  to  the  height  of 
about  600  feet,  is  constructed  partly  of  limestone,  which  consists  of  num- 
mulites and  microscopic  fossil  animalcules  that  form  a  cement  for  the  larger 
shells. 

There  exists  in  the  north  of  France  an  extensive  tract  of  country,  one  hundred 
and  eighty  miles  long,  and  about  ninety  in  breadth,  within  whose  limits  Paris  is 
included.  This  region  is  termed  by  geologists  the  Paris  Basin,  and  the  exterior 
crust  of  the  earth  is  here  composed  of  layers  or  strata  of  sand,  marl,  and  lime- 
stone— alternating  with  beds  of  plaster  of  Paris,  (gypsum)  and  flinty  matter. 
These  vast  beds  of  marl  and  limestone  are  full  of  foraminiferous  and  infusorial 
forms,  and  deposits  of  great  thicknesses  have  been  discovered,  which  are  entirely 
constituted  of  nummulites  no  larger  than  a  grain  of  millet  seed.  The  limestone 
from  the  quarries  of  Gentilly  abound  to  such  an  extent  with  microscopic  struc- 
tures, that  a  cubic  inch  is  calculated  to  contain  on  an  average  no  less  than 
58,000  shells,  and  the  beds  thus  constituted  are  of  great  extent  and  thickness. 
It  is  even  asserted  by  geologists  as  an  undoubted  fact,  that  the  edifices  of  the 
splendid  capital  of  France,  as  well  as  of  the  towns  and  villages  of  the  neighboring 
provinces,  are  almost  entirely  built  of  stones  composed  of  the  shells  of  foramini- 
ferous animals ;  and  that  these  minute  fossils  are  scarcely  less  numerous  in  other 
tertiary  formations,  extending  in  the  south  of  France  from  Champagne  to  the 
sea.  They  likewise  abound  in  the  strata  of  the  Gironde,  and  in  those  of  the 
basin  of  Vienna.  The  invisible,  calcareous  polythalamia,  or  many-chambered 
shells,  form,  according  to  Ehrenberg,  the  compact  earth  and  rocks  of  Central 
North  America,  and  constitute  immense  deposits  at  the  sources  of  the  Mississippi. 
Even  the  stupendous  chain  of  the  Andes,  belonging,  as  it  does,  to  the  chalk 
formation,  is  conjectured  to  have  been  originally  composed  of  minute  organized 
remains,  which  have  since  been  changed  by  volcanic  action. 

Vast  beds  of  animalcular  remains  occur  in  Patagonia,  the  extent  and  arrange- 
ment of  which  is  thus  described  by  Darwin  :  "  Here  along  the  coast  for  hun- 
dreds of  miles,  we  have  one  great  tertiary  formation,  including  many  tertiary 
shells,  all  apparently  extiuct.  The  most  common  shell  is  a  massive,  gigantic 
oyster,  sometimes  even  a  foot  in  diameter.  The  beds  composing  this 
formation  are  covered  by  others  of  a  peculiar,  soft,  white  stone,  including 
much  gypsum,  and  resembling  chalk,  but  really  of  the  nature  of  pumice 


FOSSIL    INFUSORIA.  61 

stone.  It  is  highly  remarkable  from  its  being  composed,  to  at  least  one-tenth  of 
its  bulk,  of  Infusoria,  and  Prof.  Ehrenberg  has  already  recognised  in  it  thirty 
marine  forms.  This  bed,  which  extends  for  five  hundred  miles  along  the  coast, 
and  probably  runs  to  a  considerably  greater  distance,  is  more  than  eight  hundred 
feet  in  thickness  at  Port  St.  Julian."  In  volcanic  products,  which  have  been  ne- 
cessarily subjected  to  the  action  of  the  most  intense  heat,  the  remains  of  Infu- 
soria have  been  detected,  incredible  as  it  may  appear.  The  Island  of  Ascension 
is  of  volcanic  origin,  and  portions  of  a  pink-colored,  porous  rock,  which  had  once 
been  flowing  lava,  were  here  taken  and  preserved  by  Darwin.  These  speci- 
mens were  examined  by  Ehrenberg,  who  discovered,  among  other  ingredients 
of  which  they  were  composed,  the  flinty  shells  of  fresh  water  infusoria. 

A  large  part  of  the  sand  of  the  great  African  desert,  consists  of  the  fossil 
shells  of  animalcules  ;  and  such  is  the  fact  in  regard  to  the  valley  of  the  Nile. 
Numerous  specimens  of  the  deposits  of  this  river,  taken  from  various  localities 
along  its  course  from  Nubia  to  the  Delta,  have  been  carefully  examined  by  Eh- 
renberg ;  and  in  such  profusion  were  fossil  sponges,  the  flinty  cases  of  Infusoria, 
and  various  species  of  Polythalamia  discovered,  that  not  a  particle  of  this  soil  of 
the  size  of  half  a  pin's  head  could  be  found,  in  which  (allowance  being  made 
for  certain  chemical  changes  that  had  occurred)  there  was  not  one,  and  often 
several,  of  these  fossil  animals. 

MUD-BANKS. — In  the  harbor  of  Wismar,  on  the  Baltic,  there  is  deposited, 
every  year,  as  appears  from  official  documents,  228,854  cubic  feet  of  mud  ;  and 
the  accumulation  has  continued  at  ihis  rate  for  more  than  a  hundred  years.  In 
the  course  of  a  century  a  deposit  has  therefore  been  made  to  the  extent  of 
22,885,400  cubic  feet,  equal  to  3,240,000  hundredweight.  These  mud-banks 
were  examined  by  Ehrenberg  in  1839  and  1840,  and  the  surprising  discovery 
was  then  made,  that  from  one-twentieth  to  one-fourth  of  the  sediment  was  com- 
posed partly  of  living  Infusoria,  and  partly  of  the  flinty  shells  of  others  that  had 
perished.  On  an  average  one-tenth  part  of  the  entire  mass  consists  of  micro- 
scopic forms,  and  hence  the  annual  deposit  of  animalcules  in  the  port  of  Wismar 
amounts  in  bulk  to  22,885  cubic  feet,  which,  if  it  was  dried,  would  weigh 
not  far  from  forty  tons.  In  the  mud-banks  of  Pillau,  Infusorial  animalcules 
were  found  in  greater  abundance  than  in  those  of  Wismar.  At  both  localities 
many  of  the  forms  were  entirely  new,  and  others  were  identical  with  living  In- 
fusoria that  inhabited  the  waters  of  the  neighboring  seas. 

The  mud  deposited  by  the  Elbe  at  Cuxhaven,  was  found  by  Dr.  Ehrenberg  to 
be  extremely  rich  in  anirnalcular  remains — nearly  half  of  the  sediment  consisting 
of  the  flinty  cases  of  Infusoria,  and  various  species  of  the  Polythalamia  or  many- 
chambered  shells.  The  flinty  cases  of  Infusoria  have  been  found  at  the  bottom 
of  the  ocean  in  the  mud  of  the  coral  islands  beneath  the  equator,  and  no  less 
than  sixty-eight  species  have  been  discovered  in  the  mud  at  Erebus  Bay,  near  the 
Antarctic  pole.  The  examination  of  the  sediment  deposited  along  the  Atlantic 
coast  of  America,  has  revealed  similar  facts.  Infusorial  animalcules  have  been  de- 


62  VIEWS    OF    THE    MICROSCOPIC    WORLD. 

tected  in  the  mud  of  Boston  harbor,  and  in  the  marine  marshes  at  New  Haven  in 
Connecticut ;  and  numerous  elegant  infusorial  structures  and  many-chambered 
shells,  have  been  found  at  Amboy  in  New  Jersey,  in  the  mud  adhering  to  oys- 
ters as  they  were  taken  from  their  beds. 

In  view  of  facts  like  these,  it  has  been  asserted  by  naturalists,  that  the  de- 
posits in  harbors,  and  the  accumulation  and  amazing  fertility  of  the  mud  of  the 
Nile,  and  probably  of  other  turbid  rivers,  are  to  be  attributed  in  a  great  measure 
to  the  agency  of  invisible  animal  life,  whose  countless  generations  succeed  each 
with  astonishing  rapidity,  leaving  the  curious  structures  in  which  they  resided  as 
the  durable  records  of  their  existence. 

These  gradual  accretions  have  been  accumulating  for  centuries,  and  are  at  this 
moment  still  in  progress.  The  sea  now  swarms  with  races  of  minute  animals, 
whose  fossil  types  are  continually  discovered  in  beds  and  strata  of  unknown  an- 
tiquity. In  salt  water,  taken  from  Cuxhaven  and  various  other  places,  no  less 
than  twenty  genera  &n&  forty  living  species  have  been  discovered  by  Ehrenberg, 
which  he  regards  as  identical  with  those  occurring  in  the  chalk  formations.  And 
out  of  twenty-eight  species  of  fossil  Infusoria  belonging  to  the  Bacillaria  or  stick- 
animalcules,  he  has  detected  fourteen  fresh  water  and  five  marine  species,  now 
living ;  the  remaining  nine  are  either  unknown  or  extinct  forms. 

The  Infusoria  that  crowd  the  seas  are  devoured  in  multitudes  by  the  common 
scallop  and  other  molluscous  animals  ;  for  when  their  stomachs  are  examined 
they  are  found  to  contain  thousands  of  microscopic  flinty  shells,  which,  from 
their  nature,  were  incapable  of  being  digested.  When  a  few  atoms  of  the  food 
which  a  scallop  has  taken  into  its  stomach  is  viewed  by  the  microscope,  it  is 
found  teeming  with  a  rich  collection  of  Infusorial  shells,  closely  resembling 
the  beautiful  structures  that  constitute  the  Richmond  deposit,  .not  only  in  form 
but  in  arrangement — so  striking  is  this  resemblance,  that  it  is  said  to  be 
extremely  difficult  to  distinguish  between  the  recent  and  ancient  remains  ;  and 
that  even  an  experienced  observer  would  be  liable  to  confound  them,  unless  the 
glass  slides,  upon  which  they  were  mounted,  were  labeled. 

The  guano  imported  from  the  isle  of  Ichaboe  has  been  found  to  contain  the 
beautiful  shell  of  the  Coscinodiscus,  and  other  Infusorial  structures  of  great 
elegance  and  richness ;  and,  as  we  gaze  upon  these  minute  cases,  we  cannot  fail 
of  being  struck  with  the  fact  of  the  great  resistance  to  decomposition  which 
they  possess.  In  this  instance  they  must  have  gone  through  the  process  of  di- 
gestion twice,  and  been  subjected  to  the  action  of  the  elements  for  centuries. 
Guano,  as  is  well  known,  is  found  within  certain  latitudes  on  uninhabited  islands, 
which  have  been,  for  ages,  the  abode  of  innumerable  multitudes  of  marine-birds. 
It  consists  of  their  excrements,  which  have  been  accumulating  for  century  after 
century,  until  they  form  layers  of  great  thickness ;  many  beds  having  been  dis- 
covered in  the  islands  of  the  Pacific,  off  the  Peruvian  coast,  having  a  depth  of 
thirty-five  or  forty  feet.  The  Infusorial  shells,  detected  in  the  guano,  are  the 
remains  of  animalcules  devoured  by  fish,  which,  afterwards,  became  the  prey  of 
voracious  sea-birds.  Thus  the  shell  passed  through  the  stomach  twice,  and  then 


FOSSIL    INFUSORIA.  63 

remained  in  the  guano-bed  for  an  unknown  length  of  time,  subjected  to  those 
common  causes  of  decay  which  turn  the  solid  rock  itself  to  dust.  But  under 
all  these  influences  they  continue  unchanged,  and  the  eye  of  the  naturalist  at 
last  detects  these  minute  structures  still  possessing  their  original  beauty,  with 
the  delicate  tracery  of  their  rich  configurations,  almost  as  sharp  and  clear  as  it 
was,  perhaps,  a  thousand  years  ago. 

INFUSORIAL  DUST. — The  fossil  shells  of  animalcules,  which  lie  mingled  with 
the.  soil  of  the  earth,  are  not  unfrequently  carried  up  into  the  air  in  the  clouds 
of  dust  that  are  raised  aloft  by  the  winds,  and  borne  along  on  the  currents  of 
the  atmosphere,  to  a  distance  almost  incredible.  Darwin  noticed  that  the  atmos- 
phere of  St.  Jago,  one  of  the  Cape  de  Verde  isles,  is  generally  hazy,  owing  to 
the  fall  of  an  impalpable  fine  dust,  of  a  brown  color.  A  small  quantity  of  the  dust 
was  collected  by  this  gentleman,  who  received  also,  from  Mr.  Lyell,  four  packets 
of  the  same  kind  of  powder,  which  fell  on  a  vessel  a  few  hundred  miles  north- 
ward of  the  Cape  Verde  Islands.  Five  parcels  were  sent  to  Dr.  Ehrenberg  for 
examination,  who  found  it  to  consist  chiefly  of  the  flinty  cases  of  Infusoria,  and 
the  siliceous  tissue  of  plants.  No  less  than  sixty-seven  distinct  kinds  of  animal- 
cules were  detected,  of  which,  sixty-four  were  fresh-water  species,  and  the 
remaining,  two  marine. 

The  same  observer,  upon  investigation,  met  with  fifteen  accounts  of  dust  falling 
upon  vessels  when  far  out  on  the  Atlantic,  off  the  coast  of  Africa.  It  has  been 
here  known  to  descend  upon  the  decks  of  ships,  at  the  distance  of  several  hun- 
dred and  even  a  thousand  miles  from  shore,  and  when  land  was  distant  to  the 
north  and  south,  full  sixteen  hundred  miles.  The  dust  is  distributed  thickly 
through  the  air,  soiling  everything  on  board,  injuring  the  eyes,  and  rendering  the 
atmosphere  so  hazy  that  vessels  have  been  known  to  run  ashore  in  consequence 
of  the  obscurity  thus  produced.  This  dust  is  believed  to  come  from  the  African 
continent,  from  the  fact  that  it  occurs  when  the  wind  is  from  that  direction,  and 
at  the  same  time  that  the  harmattan  prevails,  which  is  a  periodical  wind  that 
blows  from  the  interior  of  Africa  towards  the  Atlantic.  Clouds  of  the  finer  par- 
ticles of  sand,  from  the  arid  deserts  of  this  continent,  are  borne  aloft  by  the 
sweep  of  the  harmattan,  and  carried  far  out  over  the  sea  upon  the  higher  cur- 
rents of  the  atmosphere.  At  the  distance  of  three  hundred  miles  from  land, 
Darwin  discovered,  in  the  fallen  dust,  particles  of  stone  the  thousandth  part  of 
an  inch  square,  mixed  with  matter  still  finer. 

In  reflecting  upon  the  facts  just  adduced,  we  see,  that  in  order  to  become 
acquainted  with  the  structure  of  the  world  we  inhabit,  it  is  not  sufficient  to  trust 
to  our  unassisted  vision.  Wonders,  and  problems  the  most  curious  and  interesting 
will  meet  the  gaze  of  the  naturalist  at  every  step  he  takes  ;  but  unless  he  ex- 
plores the  secrets  of  nature  with  the  magic  glass  of  the  microscope,  half  of  the 
treasures  of  truth  will  be  still  unrevealed  :  sealed  from  his  vision  by  impenetrable 
darkness. 


64  VIEWS    OF    THE    MICROSCOPIC    WORLD. 

A  question  naturally  arises,  what  are  the  ends  which  these  Infusorial  atoms 
subserve  when  living,  whose  remains  form,  either  partially,  or  wholly,  such  ex- 
tensive portions  of  the  surface  of  the  earth  ?  To  them  have  been  attributed  malig- 
nant influences  ;  for  the  various  epidemics,  which  at  intervals  have  swept  down  our 
race,  have  been  supposed,  by  some,  to  originate  in  a  "  living  cloud  ''  of  existences, 
dwelling  in  the  air.  But  of  this  we  know  nothing  certain,  and  a  more  satisfac- 
tory answer  cannot  be  given  than  that  which  is  contained  in  the  words  of  Professor 
Owen,  who  thus  unfolded  his  views  upon  this  subject,  in  one  of  his  lectures  : — 
"  Consider  their  incredible  numbers,  their  universal  distribution,  their  insatiable 
voracity,  and  that  it  is  the  particles  of  decaying  vegetable  and  animal  bodies 
which  they  are  appointed  to  devour  and  assimilate.  Surely  we  must,  in  some 
degree,  be  indebted  to  these  ever  active,  invisible  scavengers  for  the  salubrity  of 
the  atmosphere,  and  the  purity  of  water.  Nor  is  this  all,  they  perform  a  still  more 
important  office  in  preventing  the  gradual  diminution  of  the  present  amount  of 
organized  matter  upon  the  earth.  For  when  this  matter  is  dissolved  or  sus- 
pended in  water,  in  that  state  of  comminution  and  decay,  which  immediately 
precedes  its  final  decomposition  into  the  elementary  gases,  and  its  consequent 
return  from  the  organic  to  the  inorganic  world ;  these  wakeful  members  of 
nature's  invisible  police  are  everywhere  ready  to  arrest  the  fugitive  organized 
particles,  and  turn  them  back  into  the  ascending  stream  of  animal  life.  Having 
converted  the  dead  and  decomposing  particles  into  their  own  living  tissues,  they, 
themselves,  become  the  food  of  larger  Infusoria,  and  of  numerous  other  small 
animals,  which  in  their  turn  are  devoured  by  larger  animals  :  and  thus  a  food, 
fit  for  the  nourishment  of  the  highest  organized  beings,  is  brought  back, 
by  a  short  route,  from  the  extremity  of  the  realms  of  organized  matter. 
These  invisible  animalcules  may  be  compared,  in  the  great  organic  world,  to  the 
minute  capillaries  in  the  microcosm  of  the  animal  body  ;  receiving  organic  matter 
in  its  state  of  minutest  subdivision,  and  when  in  full  career  to  escape  from  the 
organic  system,  and  turning  it  back,  by  a  new  route,  towards  the  central  and 
highest  point  of  that  system." 


MINUTE    AQUATIC    ANIMALS.  65 

CHAPTER   III. 

MINUTE    AQUATIC    ANIMALS. 

"  Then  sweet  to  muse  upon  His  skill  displayed 
(Infinite  skill)  in  all  that  he  has  made  ! 
To  trace  in  nature's  most  minute  design, 
The  signature  and  stamp  of  power  divine  : 
Contrivance  intricate,  expressed  with  ease, 
Where  unassisted  sight  no  beauty  sees; 
The  shapely  limb  and  lubricated  joint 
"Within  the  small  dimensions  of  a  point; 
Muscle  and  nerve  miraculously  spun, 
His  mighty  work  who  speaks  and  it  is  done." — COWPER. 

THE  POLYPE. — This  singular  animal,  of  which  there  are  several  species,  is 
found  abundantly  in  ponds  and  brooks,  attached  to  the  leaves  of  aquatic  plants, 
and  to  the  surface  of  twigs  and  branches  that  have  fallen  in  the  water.  Its  body, 
which  simply  consists  of  a  collection  of  cells,  formed  of  grains  of  green  and 
brown  matter,  possesses  the  power  of  expansion  and  contraction,  and  appears, 
when  extended,  in  the  shape  of  a  jelly-like  tube,  about  the  size  of  a  bristle ; 
tapering  from  the  upper  to  the  lower  extremity,  and  having  a  length  ranging 
from  one-quarter  to  three-quarters  of  an  inch.  The  mouth  is  furnished  with 
feelers  or  arms,  which  vary  in  number,  in  different  specimens,  from  six  to  sixteen, 
and  are  employed  by  the  animal  for  the  purpose  of  seizing  its  food.  Though 
appearing  to  the  unaided  eye  as  attenuated  threads,  the  microscope  shows  them 
to  be,  in  fact,  slender  tubes  filled  with  a  fluid,  and  consisting  of  a  series  of  cells  like 
the  body  of  the  animal.  When  contracted  the  polype  appears  like  a  tiny 
ball  of  jelly,  hardly  one-tenth  of  an  inch  in  diameter,  and  the  long  arms  or 
feelers  shrink  into  little  conical  eminences,  ranged  in  a  circle  around  the  upper 
part  of  the  body. 

Figures  97,  98,  99  and  100  present  a  magnified  view  of  several  polypes,  in 
different  states  of  contraction,  with  their  prey  within  them.  A  species,  termed 
from  its  color  the  Green  polype,  is  delineated  in  figures  97  and  98  and  another 
kind,  the  Brown  polype,  is  represented  in  different  attitudes  in  figures  99  and  100. 
The  small  circles  exhibit  the  specimens  of  their  natural  size.  The  mouth  of  the 
polype  is  unfurnished  with  teeth,  and  presents  different  appearances,  according  as 
it  is  more  or  less  contracted ;  at  one  time  assuming  the  form  of  a  cone,  and  at  an- 
other appearing  cup-shaped,  with  an  aperture  in  the  centre,  capable  of  great  ex- 
pansion for  the  reception  of  its  food.  This  last  form  is  shown  in  figure  98, 
where  the  animal  is  seen  gorging  its  prey.  The  polype  feeds  upon  small  crustace- 
ous  animals,  worms  and  Iarva3  ;*  and  when  in  search  of  food  extends  its  body  and 

*  Larvae  are  the  young  of  insects  in  their  caterpillar  state. 
5 


66 


VIEWS    OF    THE    MICROSCOPIC    WORLD. 
Fig.  97. 


Fig.  98. 


feelers  to  the  utmost,  spreading  out  the  latter  in  different  directions,  so  as  to 
command  an  extensive  field ;  as  soon  as  an  animal  conies  within  their  range  the 
feelers  twine  themselves  around  it,  and  gradually  contracting,  convey  the  prey  to 
the  mouth  of  the  polype.  A  polype  in  the  attitude  of  watching  for  its  prey  is 
represented  at  5,  in  figure  9V.  It  sometimes  occurs,  that  the  animal  attacked 


MINUTE    AQUATIC    ANIMALS. 
Fig.  99. 


67 


Fig.  100. 


VIEWS    OF    THE    MICROSCOPIC    WORLD. 


by  the  polype  moves  so  rapidly  as  to  prevent  the  assailant  from  instantly  secur- 
ing his  victim ;  in  such  a  case  the  latter  is  seen  to  sink  into  the  water  after  its 
attack,  and  remain  to  all  appearance  lifeless  for  the  space  of  a  few  seconds,  before 
it  regains  its  usual  vigor.  Naturalists  have  consequently  been  led  to  suppose 
that  the  polype  possesses  the  power  of  paralyzing  its  prey  by  weak  electric  shocks, 
in  the  manner  of  the  torpedo  and  the  electric  eel.  In  this  way  only  can  they 
account  for  the  fact,  that  such  slender  organs  as  the  arms  of  the  polype  are 
able  to  secure  animals  comparatively  so  large  and  powerful,  when  striving  with 
then*  utmost  power  to  escape  from  the  fatal  coils  in  which  they  are  entwined. 
Dr.  Mantell  once  beheld  a  lively  polype  seize  two  large  worms  at  the  same 
instant,  when  its  extended  arms  were  so  attenuated  that  they  were  scarcely  visi- 
ble without  the  aid  of  a  lens ;  and  yet  the  worms,  though  struggling  desperately 
for  their  lives,  were  unable  to  burst  from  the  slender  bonds  that  encircled  them, 
and  in  an  instant  lost  all  power  of  motion :  the  same  effect  is  produced  upon 
the  Water-flea,  an  extremely  vivacious  little  creature,  when  struck  by  the  feelers 
of  the  polype.  The  power  exerted  by  the  arms  is  considered  to  be  electric  in 
its  nature,  inasmuch  as  the  polype  has  never  been  found  to  possess  a  sting  or 
destructive  weapon  of  any  kind. 

The  stomach  of  the  polype  consists  of  the  whole  internal  cavity  of  the  crea- 
ture, and  when  its  prey  has  been  seized  and  devoured,  the  body  and  feelers  are 
no  longer  extended,  but  contract,  as  shown  in  figures  99  and  100,  where  a,  figure 
99,  represents  a  polype  partially  contracted,  and  figure  100  one  entirely  so. 
While  the  process  of  digestion  is  advancing,  the  polype  is  very  sluggish,  and  the 
whole  nutritive  fluid  is  disseminated  throughout  the  internal  surface,  both  of  the 
body  and  the  feelers,  imparting  to  them  a  colored  appearance ;  thus,  when  a 
red  worm  has  been  devoured,  the  hue  of  the  prey  tinges  the  entire  surface  of 
the  polype.  The  polype  multiplies  by  buds  and  shoots,  which  spring  out  of  the 
trunk  of  the  parent,  as  shown  in  figure  99.  If  it  is  kept  in  a  vessel  of  water, 
and  well  provided  with  food,  two  or  three  shoots  are  seen,  when  the  weather 
is  warm,  growing  out  of  its  body  at  the  same  time,  and  from  these  branches 
while  yet  attached  to  the  parent  trunk,  other  sprouts  and  offsets  push 
vigorously  forth.  When  a  young  polype  is  about  to  come  into  existence,  that 
part  of  the  body  from  which  it  will  grow  swells  beyond  its  natural  size,  as  shown 
at  a,  figure  97.  This  protuberance  continues  gradually  to  increase,  and  when  a 
sufficient  enlargement  is  attained  the  head  of  the  young  polype  appears,  and  its 
arms  are  protruded,  and  by  the  aid  of  the  latter  it  now  supplies  itself  with  food, 
in  the  manner  of  the  parent,  as  seen  at  c  in  the  same  figure.  Until  nearly  the 
time  when  it  separates  from  its  parent,  the  young  polype  possesses  an  internal 
communication  with  the  latter,  and  also  a  common  sensation  ;  for  if  one  is  dis- 
turbed and  contracts  the  other  directly  does  the  same. 

The  polype  is  endowed  with  the  wonderful  property  of  reproducing  any  organs 
of  which  it  has  been  deprived  ;  for  its  body,  however  mutilated,  soon  supplies  its 
deficient  members,  and  the  creature  becomes  once  more  a  perfect  and  complete 
animal.  If  a  polype  is  divided  across  into  two  parts,  the  upper  portion,  contain- 


MINUTE    AQUATIC     ANIMALS.  69 

ing  the  arms,  speedily  provides  itself  with  a  new  body  and  tail,  and  the  lower 
part  pushes  forth  a  fresh  body  and  head  with  its  slender  arms.  If  the  animal  is 
slit  down  from  the  head  to  the  tail,  but  is  not  quite  severed,  each  of  the  two 
parts,  thus  left  hanging  together,  becomes  a  perfect  polype,  and  they  live  and 
roam  through  the  water  indissolubly  linked  to  one  another.  Nay,  more,  if  a 
polype  is  turned  inside  out,  it  soon  accommodates  itself  to  this  new  arrangement ; 
for  the  original  outer  skin,  now  lining  the  interior  cavity,  performs  the  office  of 
digestion  ;  while  the  coating  of  the  former  stomach  becomes  the  covering  or 
skin  of  the  polype. 

The  possession  of  this  strange  faculty  by  the  polype  is  not  a  matter  of 
inference  or  conjecture  ;  inasmuch  as  it  has  been  proved  by  experiments,  beyond 
the  possibility  of  a  doubt.  It  was  first  discovered  about  a  century  ago,  by  Mr. 
Trembly,  of  Holland,  whose  statements  were  afterwards  verified  in  England  in 
every  important  particular,  by  the  experiments  of  Mr.  Henry  Baker,  of  the 
Royal  Society  ;  and  still  later  by  Pritchard,  who  thus  details  one  of  his  experi- 
ments. "  Having  selected  a  brown  polype  out  of  a  glass  vase  containing  a  good 
supply  of  them,  none  of  which  had  more  than  seven  arms,  I  severed  it  obliquely, 
the  upper  part  comprising  the  greater  portion  of  the  head  and  four  arms ;  the 
lower  part  being  the  tail  with  the  remainder  of  the  head  and  two  arms.  These 
pieces  were  then  put  in  a  four-ounce  phial  of  water,  with  a  few  small  Crustacea, 
where  they  sunk  to  the  bottom,  apparently  lifeless.  Three  hours  after  the 
operation  I  examined  them,  and  found  them  in  the  same  state. 

Twelve  hours  after  this  I  found  the  lower  part  attached  to  the  side  of  the  phial 
by  its  tail,  with  its  arms  extended  in  quest  of  food  ;  the  upper  one  still  remaining 
at  the  bottom,  but  with  its  arms  extended  like  the  other. 

On  the  second  day,  a  new  tail  was  completed  to  the  upper  part  of  the  polype, 
and  the  rudiments  of  additional  arms  were  developed  in  both,  and  each  portion 
appeared  in  good  health.  On  the  third  day,  the  new  arms  were  nearly  of  the 
same  size  as  the  others,  and  in  less  than  a  week  each  of  the  two  polypes  had  a 
young  one  sprouting  from  it.  The  most  curious  circumstance  connected  with 
this  experiment  was,  that  the  two  new  polypes  had  each  ten  arms,  while  that 
from  which  they  were  produced,  as  well  as  those  which  were  in  the  same  vessel, 
had  only  six  or  seven.1' 

The  number  of  parts  into  which  this  creature  is  divided  presents  no  obstacle 
to  the  operation  of  this  extraordinary  law  o% vitality ;  for  a  single  polype  has 
been  cut  into  ten  pieces,  and  each  part  soon  became  a  complete  animal. 

THE  ROUND  LYNCEUS,  OR  MONOCULUS. — This  name  is  given  to  the  curious 
little  creature,  which  is  shown  highly  magnified  in  figure  101.  It  is  covered 
with  a  delicate  shell,  presenting  by  its  fine  reticulations  the  appearance  of  mo- 
saic work.  This  envelope,  with  its  minute  divisions,  is  beheld  in  the  drawing  at 
a,  and  encases  nearly  the  entire  body  of  the  animal.  In  some  species  the  shell 
is  adorned  with  diamond-shaped  figures,  in  others  its  surface  is  composed  oi, 
hexagons  like  that  of  a  honey -comb ;  and  a  diversity  of  other  angular  figures 


70  VIEWS    OF    THE    MICROSCOPIC    WORLD. 

embellish  the  cases  in  the  different  remaining  varieties  of  the  Lynceus.  The 
shell  is  perfectly  transparent,  and  consists  of  a  single  piece  without  hinge  or 
joint ;  being  sufficiently  elastic  to  permit  the  animal  to  open  it  at  pleasure.  The 
position  of  the  edges  of  the  opening,  is  indicated  in  the  figure,  on  the  under  side, 
by  the  letter  b.  Not  only  is  the  animal  itself  protected  by  this  delicate  case,  but  it 
affords  a  secure  retreat  for  the  young  when  danger  is  near.  They  then  escape 
from  the  approaching  peril  by  swimming  within  the  shell  of  the  parent,  which 
the  latter  opens  for  their  reception,  and  closes  as  soon  as  their  entrance  is  effected. 
The  two  eyes  of  the  Lynceus  at  d  are  of  different  sizes  and  are  of  a  deep  black 
hue  ;  while  the  rest  of  the  animal  is  buff,  approaching  to  orange.  The  beak  is 
seen  at  c,  and  the  two  horns  or  feelers  at  g.  Within  the  shell  is  a  row  of  four 
false  feet,  easily  discerned,  that  assist  the  Lynceus  in  creeping  along  the  stalks 
of  plants,  to  which  it  attaches  itself  by  pressing  their  sides  with  the  edges  of  its 
shell  in  the  manner  of  a  pair  of  pincers.  These  members  also  subserve  another 
purpose,  causing  the  animal,  as  it  advances  through  the  water,  to  proceed  with 
a  revolving  motion  ;  in  which  action  it  is  also  aided  by  the  appendage  /,  which, 
striking  against  the  water  like  a  fin,  renders  the  rotatory  motion  of  the  Lynceus 
more  rapid.  This  organ,  which  resembles  a  tail,  is  armed  with  two  strong 
claws,  is  forked  at  the  extremity,  and  fringed  along  the  edges  with  rows  of  hairs. 
The  Lynceus  feeds  on  animalcules,  and  is  the  food  of  larger  water  insects.  The 
position  of  the  stomach  is  indicated  in  the  drawing  by  the  curved  figure  within 
the  shell. 

THE  SMALL  WATER-FLEA. — This  little  animal  is  found  abundantly  in  ponds 
and  brooks  during  the  summer  months,  sporting  about  in  the  waters  with  great 
activity.  According  to  Pritchard,  they  are  usually  colorless  in  ponds  covered 
with  herbage,  but  in  small  collections  of  rain  water  in  a  loamy  soil  they  glow 
with  a  fine  bright  red  hue.  A  drawing  of  this  animal,  of  its  real  size,  is  seen  in 
figure  102,  and  a  magnified  representation  in  figure  103.  The  body  of  the 
W'ater-flea  is  covered  with  a  kind  of  armor,  formed  of  plates  of  shell  that  over- 
lap each  other,  and  are  capable  of  being  moved  sideways  as  well  as  up  and  down. 

Their  ends  do  not  meet  on  the  underside,  thus  affording  a  sufficient  space  for  the 
insertion  and  motion  of  the  organs  of  respiration,  which  are  seen  at  a,  but  are 
exhibited  with  greater  distinctness  ^  c,  where  they  are  more  highly  magnified. 

The  eye  of  the  Water-flea,  show  at  of,  is  of  a  dark  crimson  hue,  and  from 
each  side  of  it,  spring  two  pairs  of  horns,  which  consist  of  numerous  joints, 
studded  with  bristles,  two  or  more  proceeding  from  each  joint. 

In  some  species  the  sexes  are  distinguished  by  them,  the  males  having  a  bulb 
about  the  middle  of  the  right  antennae,  or  horns,  as  shown  in  figure  104.  The 
appendages  which  are  seen  attached  to  the  lower  extremity  of  the  animal  are 
the  bags  containing  its  eggs,  and  which  are  together,  nearly  equal  in  size  to  the 
bulk  of  the  insect  itself.  Below  these  sacks  the  tail  is  forked  and  adorned  with 
a  plume  of  fringed  hair.  In  most  instances  the  shell  of  the  Water-flea  is  trans-, 
parent  like  crystal,  but  it  is  frequently  embellished  with  beautiful  tints.  Some 


106 


105. 


MINUTE    AQUATIC    ANIMALS.  7l 

are  of  a  bluish  green,  and  others  red,  with  the  receptacles  of  the  eggs  of  a  green 
color.  In  the  specimen  from  which  the  drawing  was  taken  the  shell  was  richly 
adorned  with  bright  red  hues. 

THE  VAULTER. — The  appellation  of  Vaulter  is  given  to  the  minute  insect 
which  is  represented,  highly  magnified,  in  figure  105.  It  derives  its  name  from 
the  circumstance  that  it  transports  itself  from  place  to  place  by  successive  leaps, 
in  the  manner  of  a  flea.  As  a  person  approaches,  it  remains  quiet  for  a  short 
time  upon  the  leaves  of  the  plant  on  which  it  happens  to  be  ;  but  soon  springs 
away  to  some  other  place,  a  motion  which  it  effects  by  bending  its  body  and 
darting  away  from  point  to  point,  by  the  force  of  the  recoil.  In  England  the 
Vaulter  appears  in  the  greatest  numbers  in  the  months  of  April  and  May,  swarm- 
ing upon  the  stalks  and  under  side  of  the  leaves  of  healthy  duck-weed,  growing 
on  the  surface  of  the  water.  Stagnant  water,  filled  with  decayed  plants,  is  de- 
structive to  them,  and  in  order  to  preserve  them,  they  must  be  provided  with 
plenty  of  clear,  pure  water.  The  Vaulter  is  very  active,  and  when  caught,  is 
usually  detected  in  the  eager  pursuit  of  its  prey.  The  encasing  shell  of  this 
creature  is  similar  to  that  of  the  Small  Water-flea,  but  differs  in  having  a  greater 
number  of  parts.  The  body  tapers  also  more  gradually,  and  the  horns  do  not  con- 
tain so  many  joints  as  those  of  the  former.  It  is  also  distinguished  from  this  insect 
by  having  under  the  beak  a  single  organ  of  respiration,  whi<?h  is  delineated  in 
figure  106.  This  instrument  is  in  constant  motion,  and  causes  a  current  of 
water  to  set  towards  the  animal,  like  the  cilia  of  the  Infusoria.  The  legs  are  ten 
in  number,  and  are  fringed  with  hairs ;  and  the  tail  of  the  Vaulter,  which  con- 
sists of  two  parts,  is  ornamented  in  the  same  manner.  The  eye  is  deeply 
imbedded  within  the  shell,  and  its  position  in  the  figure  is  indicated  by  the  let- 
ter c.  The  upper  part  of  the  Vaulter  gleams  with  a  bright  red  hue  of  various 
tints,  fading  down  to  salmon  color  on  the  under  side  of  the  body  and  legs ; 
while  the  tail,  the  tufts  of  hair  which  fringe  the  legs,  and  the  horns  or  feelers, 
are  of  a  bluish  green.  The  Vaulter  is  only  one  three-hundredth  of  an  inch  in 
length. 

THE  LARVA  OF  A  SMALL  BOAT-FLY. — This  insect  is  so  called  from  its  re- 
semblance in  form  to  a  boat.  They  swim  on  their  backs,  and  propel  themselves 
with  considerable  force  by  means  of  their  hinder  feet,  which  are  shaped  like  oars. 
Pritchard  observes,  that  they  are  found  during  the  spring,  playing  upon  the  sur- 
face of  ponds  and  streams,  and  immediately  seeking  the  bottom  when  disturbed. 
They  acquire  their  full  richness  of  color,  and  attain  their  perfect  state  in  the  fall 
months,  at  which  time  they  deposit  their  eggs,  which  are  small  in  size,  and  con- 
sist of  a  jelly-like  substance.  As  the  young  advance  towards  maturity,  they 
shed  their  skins  several  times ;  at  which  periods  they  are  colorless  throughout, 
except  the  eyes,  which  are  of  a  light  crimson. 

They  acquire  their  peculiar  tints  sometime  afterwards,  the  lower  part  of  the 
body  changing  through  every  variety  of  hue,  from  a  pale  yellow  to  a  rich  car- 


72  VIEWS    OF    THE    MICROSCOPIC    WORLD. 

mine.  The  insect  possesses  the  form  depicted  in  figure  10 7,  which  presents  a 
magnified  view  of  its  under  side.  The  head  (a),  is  of  a  yellow  color,  and  on  each 
side  of  it  are  placed  two  reticulated  eyes  (6  6),  of  a  deep  crimson  hue.  This  crea- 
ture has  three  pairs  of  feet,  fringed  with  hair  ;  the  first  of  which  often  escape 
observation  from  their  color  and  position.  The  second  pair  are  generally  thrown 
forward  in  a  swimming  position,  as  displayed  in  the  figure.  The  hinder  pair  are 
the  strongest,  and  are  armed  at  their  extremities  with  claws.  The  beak  is  hard 
and  pointed,  and  in  some  of  the  larger  species  is  capable  of  inflicting  a  severe 
Fig  IDS  puncture.  In  the  preceding  figure  this  organ  is  shown  fore- 

shortened, but  in  figure  108,  the  head  and  beak  of  the  insect 
are  represented,  highly  magnified.  The  compound  eyes  are 
seen  at  d  d,  and  the  beak  at  6.  The  latter  consists  of  several 
parts,  is  cased  in  a  horny  substance,  grooved  down  the  middle, 
and  terminates  in  a  fine,  hard  point.  The  inner  wings  of  the 
^Boat-fly,  when  arrived  at  maturity,  are  fragile  and  delicate, 
and  are  protected  from  injury,  like  those  of  many  other  insects, 
by  hard,  shelly  cases,  under  which  they  are  neatly  and  com- 
pactly folded.  The  insect  is  ornamented  with  long  hairs, 
which,  along  the  lower  part  of  the  body  and  down  the  middle, 
are  arranged  in  thick  tufts.  These  tufts  appear  to  be  intended 
*For  the  purpose  of  permitting  the  creature  to  float  at  plea- 
sure, without  any  exertion,  and  this  result  is  effected  in  the  following  way  :  the 
Larva  first  rises  to  the  top  of  the  water,  and  then  elevating  the  lower  end  of  its 
body  above  the  surface,  lifts  up  the  rows  of  hair  on  either  side  of  its  body,  suf- 
fering the  air  to  fill  the  channel  or  groove  that  they  before  occupied.  Retaining 
the  air  in  this  cavity,  it  thus  becomes  specifically  lighter  than  the  water,  and  now 
floats  at  its  ease  upon  the  surface.  When  the  insect  wishes  to  descend,  it  smooths 
down  the  rows  of  hair  into  their  former  place,  by  the  aid  of  its  feet,  and  thus 
expelling  the  air,  renders  itself  heavier  than  the  water,  and  sinks.  The  margin 
of  the  body  of  this  little  creature  is  naturally  of  a  bright  carmine,  the  central 
portions  of  a  yellowish  brown,  and  the  legs  of  a  delicate  straw  color.  Its  food 
consists  of  the  eggs  and  larvae  of  water-insects,  and  it  often  awaits  its  prey  by 
lying  at  the  bottom  of  the  water  with  its  beak  upwards,  ready  for  assault.  In 
this  position  it  remains,  until  its  victim,  unwarily  descending,  falls  in  a  moment 
into  the  power  of  its  destroyer. 

THE  LARVA  OF  A  SPECIES  OF  WATER-BEETLE. — The  eggs  from  which  this 
Larva  is  produced  are  found,  in  the  spring  and  summer,  adhering  to  the  surfaces 
of  aquatic  plants.  They  are  enclosed  in  a  bag,  a  little  smaller  in  size  than  a 
pea,  which  is  fastened  by  a  slight  thread  to  the  herbage. 

These  eggs  are  readily  hatched  by  placing  them  in  a  vessel  of  water,  and 
exposing  them  to  the  sun  for  a  few  days  ;  when  the  young  soon  appear,  moving 
about  the  fluid  with  great  activity.  At  first  they  are  of  a  dark  hue,  but  in  a 


MINUTE    AQUATIC    ANIMALS.  *73 

short  time  they  shed  their  skin,  during  which  process  their  color  fades  ;  at  the 
same  time  their  vivacity  forsakes  them  and  they  abstain  from  food. 

As  they  recover,  their  color  changes  again,  and  diversified  tints  adorn  their 
bodies.  These  creatures  are  extremely  voracious  ;  for  if  they  are  placed  in 
water  with  other  insects,  the  latter  are  soon  found  to  be  either  mutilated  or 
destroyed. 

This  Larva  is  seen  of  its  natural  size  in  figure  109,  and  a  magnified  representa- 
tion is  given  in  figure  110,  which  exhibits  the  animal  soon  after  it  has  cast  its 
skin  :  when,  on  account  of  the  transparency  of  the  new  skin,  it  is  in  the  best 
condition  to  be  viewed  by  the  microscope,  as  the  whole  interior  organization  is 
then  visible.  This  insect  is  furnished  with  two  strong  jaws,  like  a  pair  of  bent 
pincers,  which  move  horizontally  and  cross  each  other  when  closed.  Their  color 
is  a  bright  chestnut,  deepening  in  tint  towards  the  points,  which  are  hard  and 
sharp.  The  animal  seizes  its  prey  with  these  instruments,  and  forcibly  draw- 
ing it  towards  itself,  makes  an  incision  on  the  body  and  sucks  out  the  juices. 
Unless  its  prey  is  of  great  strength  the  Larva  does  not  kill  it  before  eating,  but, 
seizing  on  any  part  within  its  reach,  devours  it  while  its  victim  is  alive.  Having 
finished  this  portion,  it  turns  the  insect  round  and  feeds  upon  a  fresh  part,  and 
thus  continues  its  repast  until  the  whole  of  its  prey  is  consumed,  except  the 
skin. 

If  the  object  of  attack  is  a  strong,  aquatic  animal  covered  with  a  shell,  the 
Larva  either  seizes  and  holds  it  firmly  grasped  until  it  is  exhausted  by  its  efforts  to 
escape  ;  or,  springing  at  it  from  time  to  time,  cuts  oft'  its  limbs  in  succession  with 
its  powerful  nippers  ;  then,  turning  the  disabled  animal  upon  its  back,  the  ferocious 
creature  pierces  the  mutilated  body,  and  imbibes  its  contents.  In  respect  to  the 
other  parts  of  the  animal,  feelers  are  seen  branching  out  from  the  head,  each 
composed  of  four  pieces,  connected  by  joints.  On  either  side  of  the  head  is  a 
cluster  of  eyes,  six  in  each  cluster ;  in  some  species  they  are  arranged  in  a  circle 
at  equal  distances  from  one  another,  while  in  others  three  or  four  are  united  in 
a  group  with  the  rest  a  little  separated  from  them.  The  organs  of  respiration 
are  seen  in  their  greatest  development  at  the  head,  and  their  course  from  thence 
to  the  tail,  through  the  entire  length  of  the  animal,  is  indicated  by  the  dark 
lines  in  the  figure.  At  the  tail  the  different  parts  unite  and  terminate  ;  tl^ey 
are  not  simple  in  their  structure,  but  numerous  lateral  subdivisions  are  thrown 
out  between  the  extremities  of  the  main  organs. 

The  entire  body  of  the  animal  is  composed  of  rings,  decreasing  in  size 
from  the  head  to  the  tail,  which  is  forked,  and  consists  of  two  strong  spines 
with  smaller  ones  branching  from  their  sides.  When  one  of  these  is  destroy- 
ed, Pritchard  observed  it  to  be  replaced  by  another,  which  seldom,  however, 
attains  the  size  of  that  which  is  lost.  The  Larva  is  provided  with  six  legs,  each 
consisting  of  three  joints  ;  bristling  with  formidable  spines,  fringed  with  hairs, 
and  armed  at  the  extremities  with  strong  claws.  The  front  part  of  the  head, 
immediately  below  the  jaws,  is  furnished  with  an  arrangement  like  the  teeth  of 
a  saw ;  but  whether  this  apparatus  is  really  composed  of  teeth  has  not  yet  been 


74  VIEWS    OF    THE    MICROSCOPIC    WORLD. 

ascertained.  This  Larva  feeds  indiscriminately  upon  all  kinds  of  aquatic  insects 
which  it  can  master,  and  is  itself  the  prey  of  the  larger  water-beetles.  When  kept 
together  by  themselves,  without  their  appropriate  food,  they  attack  and  devour 
one  another.  If  they  are  confined  in  separate  vessels  for  a  few  days  and  then 
put  together,  they  soon  engage  in  fierce  conflicts,  seizing  each  other  with  their  for- 
midable jaws  whenever  a  favorable  opportunity  occurs,  and  displaying  the  greatest 
courage ;  the  assailant  sometimes  engaging  another  of  twice  its  own  size. 
These  creatures  move  very  swiftly  through  the  water,  occasionally  rising  to  the 
surface  for  the  purpose  of  breathing.  They  sometimes  hold  their  tails  above  the 
water  to  attain  the  same  end,  admitting,  while  in  this  attitude,  fresh  portions  of 
air  into  the  respiratory  organs  by  means  of  the  orifices  near  the  lower  extremity 
of  the  body.  As  these  animals  gradually  increase  in  size  they  become  more  and 
more  inactive,  and  are  often  infested  with  the  Bell-shaped  animalcules.  If  this  is 
the  case  the  animalcules  become  exceedingly  numerous,  and  when  the  Larva 
arrives  at  maturity,  the  surface  of  its  body  then  appears  to  the  naked  eye  to  be 
covered  with  a  fine  down,  which  is  nothing  else  than  a  vast  collection  of  Bell- 
shaped  animalcules. 

THE  LURCO,  OR  GLUTTON. — This  aquatic  animal  is  shown  in  Fig.  111.  It 
resembles  a  caterpillar  in  form,  and  being  transparent  to  a  certain  degree,  affords 
an  excellent  object  for  the  microscope,  the  internal  structure  of  the  creature  be- 
ing clearly  discerned  under  a  good  light.  The  Lurco  is  usually  found  in  collec- 
tions of  water  where  grass  and  weeds  are  lying  partially  decayed.  When  the 
day  is  bright  they  rove  upon  the  surface  of  the  water,  but  cluster  together  at 
the  bottom  in  cloudy  weather.  No  difficulty  is  experienced  in  preserving  them 
alive  for  months  in  vessels  of  water,  where  they  increase  rapidly  both  in  size  and 
numbers,  if  bountifully  supplied  with  their  accustomed  food.  Pritchard  states, 
that  having  caught  in  the  month  of  June  a  number  of  specimens,  which  were 
nearly  one- fifth  of  an  inch  in  length,  he  kept  them  in  a  vessel  holding  about  three 
quarts  until  the  month  of  October ;  they  had  been  plentifully  provided  with 
monoculi,  and  by  this  time  had  become  very  numerous,  congregating  together 
in  masses  of  considerable  size,  and  some  of  the  larger  individuals  had  grown  to 
the  length  of  three-fifths  of  an  inch.  The  Lurco  is  not  possessed  of  feet,  but  is 
furnished  with  small  tufts  of  hair  set  along  its  sides.  Its  mouth  is  fringed  with 
hairs,  and  when  open  has  the  shape  of  a  pear.  The  gullet,  connecting  the  mouth 
with  the  first  stomach,  is  capable  of  instantaneously  expanding  to  a  great  extent : 
it  is  never  complete!}7  closed,  and  the  prey  of  the  Lurco,  which  it  always  swallows 
alive,  may  frequently  be  discerned  moving  about  in  the  first  stomach  and  seek- 
ing to  escape  through  the  mouth.  The  whole  body  of  the  creature  is  divided 
into  a  number  of  stomachs,  separated  from  each  other  by  a  transparent  ring  of 
muscles,  which  expands  and  contracts  to  a  considerable  extent. 

The  Lurco  is  endowed  with  very  strong  digestive  powers,  for  its  favorite  food 
is  monoculi,  which  are  covered  with  a  hard,  shelly  case.  These  it  swallows  entire 
with  great  voracity,  filling  itself  to  repletion,  when  it  remains  torpid  like  the 


'.'• 


MINUTE    AQUATIC    ANIMALS.  75 

boa  constrictor,  as  the  process  of  digestion  is  advancing.  A  Lurco  of  an  average 
size  has  been  known  to  devour  seven  monoculi,  like  those  delineated  in  figure 
101,  in  the  course  of  half  an  hour.  At  the  end  of  this  time  five  of  them  were 
seen  moving  in  the  first  stomach,  and  the  remaining  two  were  lying  in  the  second 
nearly  dead.  This  voracious  creature  often  swallows  monoculi  whose  diameter 
is  often  longer  than  the  ordinary  width  of  its  own  body.  In  the  figure  three  of 
its  victims  are  seen  within  the  body  of  the  animal. 

EELS  IN  PASTE. — If  a  paste  is  made  of  flour  and  water,  and  kept  for  a  few 
days,  its  surface  will  be  covered  with  a  collection  of  minute,  light  brown  animals 
resembling  eels  in  shape.  Not  the  slightest  indication  of  life  can  be  found  in 
the  paste  when  freshly  made  ;  indeed  the  heat  to  which  it  has  been  subjected  in 
boiling  would  inevitably  destroy  any  previous  vitality  ;  and  yet  but  a  short  time 
elapses  ere  it  swarms  with  countless  living  forms,  whose  existence,  under  ordi- 
nary circumstances,  terminates  only  with  the  entire  consumption  of  the  paste 
upon  which  they  feed.  Adams,  in  his  work  on  the  Microscope,  remarks,  that 
there  are  four  kinds  of  eels  found  in  paste  ;  that  during  the  fall  and  winter  they 
are  oviparous*  and  the  young  eels  may  then  be  perceived  proceeding  from  the 
eggs  ;  but  at  other  times  they  are  viviparous.  The  chief  figure  in  drawing  112 
is  a  magnified  view  of  a  full  grown  eel  of  the  first  kind.  The  position  of  the 
mouth  is  denoted  by  the  letter  a,  and  so  perfectly  distinct  is  this  organ,  that 
under  the  microscope  it  can  be  seen  in  motion  as  the  animal  feeds  upon  the  paste ; 
c,  c,  and  c,  are  light  brown  particles  of  matter,  which  are  found  in  the  interior  of 
the  animal ;  d,  df,  c?,  &c.,  are  young  eels  in  the  same  situation. 

When  a  full  grown  eel  is  cut  in  two,  the  young  eels  and  the  brown  particles 
are  at  once  expelled.  The  result  of  such  a  dissection  is  shown  in  the  group 
around  the  central  eel,  where  the  individuals  are  magnified  to  the  same  extent  as 
the  parent  animal.  The  smaller  eels,  found  on  the  surface  of  the  paste,  and 
which  have  not  arrived  at  maturity,  exhibit  the  same  appearance  as  the  speci- 
mens composing  this  group,  and  display  no  internal  organization,  which  only 
becomes  apparent  as  they  advance  in  size.  So  prolific  is  this  animal  that  it  often 
contains,  when  mature,  a  hundred  living  eels  at  one  time. 

The  second  species,  which  is  oviparous,  is  delineated  in  figure  113,  and  is  both 

Fig.  113. 


Oviparous,  producing  young  from  egg8. 


V6  VIEWS    OF   THE   MICROSCOPIC    WORLD. 

different  in  form  and  smaller  than  the  first.     The  third  sort  is  also  oviparous, 
Fig.  us.  and  is  exhibited  in  figure  114.      In   figure        Fi    m 

115  three  extremely  small  eels  are  shown, 
which  are  specimens  of  the  fourth  class. 

The  manner  in  which  these  animals 
originate  has  given  rise  to  much  discus- 
sion, inasmuch  as  they  are  not  only  found 

to  be  viviparous ;  but  are  also  said  to  be  produced  when  the  paste  is 
covered.  An  opinion  has  therefore  been  entertained  that  their  origin 
is  spontaneous  ;  a  circumstance  which  would  be  at  variance  with  all 
our  experience.  Dr.  Ehrenberg,  in  respect  to  Infusoria,  has  experimented  for 
many  years  with  pure  spring  water,  distilled  water,  and  rain  water ;  with  and 
without  vegetables,  boiled  and  unboiled,  and  always  with  the  following  results ; 
that  when  open  vessels  were  exposed  to  the  air  animalcules  were  discovered  after  a 
longer  or  shorter  time,  according  to  the  temperature,  and  other  attendant  cir- 
cumstances ;  but  if  the  vessels  were  closed,  infusorial  life  was  rarely  detected. 
In  view  of  these  facts  it  may  be  inferred,  that  when  eels  are  said  to  have  been 
found  in  paste  that  was  covered,  that  sufficient  precautions  had  not  been  adopted 
to  exclude  it  entirely  from  all  access  of  the  atmosphere,  and  that  invisible  eggs  or 
germs,  like  those  of  Infusoria,  were  either  contained  in  the  air  that  floated  at 
first  above  the  p^ste  in  the  jar,  or  were  borne  upon  slight  currents  into  the  vessel, 
through  minute  apertures  that  escaped  observation. 

The  fact  that  the  eels  of  paste  are  viviparous  cannot  fairly  be  urged  as  an 
argument  against  their  generation  from  a  known  cause,  inasmuch  as  the  same 
individual  is  both  oviparous  and  viviparous ;  six  young  eels  and  twenty-two 
eggs  having  been  found  in  a  single  specimen  at  one  time.  In  their  modes  of 
increase  they  therefore  resemble  numerous  species  of  Infusoria,  which  are  not 
confined  to  one  method  of  production,  but  multiply  in  various  ways. 

THE  VINEGAR  EEL. — If  a  small  quantity  of  good  vinegar  is  viewed  in  a  wine- 
glass, by  the  naked  eye,  under  a  strong  light,  the  fluid  will  generally  be  seen 
filled  with  slender  threadlike  bodies  in  rapid  motion.  These  are  the  eels  of 
vinegar,  which,  when  studied  under  the  microscope,  are  found  to  be  larger  than 
the  Paste  eel  but  not  so  thick  ;  the  tail  is  also  smaller,  more  tapering,  and 
moves  with  greater  rapidity.  Like  the  Paste  eel  they  increase  by  eggs,  and  also 
bring  forth  their  young  alive.  The  eels  of  vinegar  are  finely  displayed  when  a 
little  reservoir  is  made'  between  two  narrow  slips  of  glass,  and  the  cavity  filled 
with  a  few  drops  of  vinegar.  If  the  fluid  is  then  magnified  by  the  solar  micro- 
scope, and  its  image  received  upon  a  large  screen,  hundreds  of  eels,  apparently 
more  than  a  foot  in  length,  will  be  seen  upon  the  screen  in  the  highest  state  of 
activity,  crossing  and  recrossing  its  surface,  and  darting  and  twisting  in  every 
direction.  Sometimes  if  a  small  piece  of  mother  floats  in  the  vinegar,  several 
eels  will  become  entangled  in  it  at  the  same  time,  and  their  rapid  evolutions  as  they 
struggle  to  escape  from  this  impediment  affords  an  interesting  spectacle.  Their 


MINUTE    AQUATIC    ANIMALS.  77 

motions  are  evidently  quickened  by  the  glare  of  the  sunlight,  that  falls  upon 
them  from  the  lenses,  and  which  they  endeavor  to  shun,  A  group  of  Vinegar 
eels  in  various  attitudes,  is  shown  in  drawing  116,  as  they  appear  when  magnified. 
Some  are  in  the  act  of  swimming,  others  are  at  rest ;  one  has  just  died,  and 
the  skeleton  of  another  is  seen  at  c.  The  breadth  of  the  dead  eel  at  a  6  is  the 
twelve  hundred  and  fiftieth  part  of  an  inch. 


78  VIEWS    OF   THE    MICROSCOPIC    WORLD. 


CHAPTER   IV. 

OF   THE    STRUCTURE    OF    WOOD    AND    HERBS. 

I  read  His  awful  name  emblazoned  high 
With  golden  letters  on  the  illumined  sky ; 
Nor  less  the  mydtic  characters  I  see 
Wrought  in  each  flower,  inscribed  on  every  tree. 

BAKBAULD. 

NATURALISTS  have  discovered  by  the  aid  of  the  microscope  that  all  plants 
consist  of  two  kinds  of  organic  matter,  essentially  distinct,  the  woody  portion 
and  the  pithy  portion;  and  that  the  several  parts  of  a  plant,  however  differing  from 
each  other  in  form,  texture,  and  appearance,  are  still  composed  of  the  same  two 
substances,  but  varying  in  the  proportion  and  arrangement.  The  woody  portion  has 
also  received  the  name  of  the  vascular  system,  while  to  the  other  division  has  been 
assigned  the  appellation  of  the  cellular  tissue  ;  and  these  will  now  be  described, 
so  far  as  is  necessary  for  the  purpose  of  this  work,  without  any  design  of  enter- 
ing fully  into  the  subject  of  vegetable  anatomy. 

WOODY  PORTION. — The  woody  part  of  a  plant,  whether  herb  or  tree,  is  not 
solid,  but  is  composed  of  a  vast  number  of  small  tubes,  extending  from  the 
roots,  and  ramifying  through  the  stem  and  branches  to  every  part  of  the  plant ; 
even  the  oldest  and  most  compact  species  of  wood  is  nothing  else  than  a  collec- 
tion of  vessels  and  cells,  the  sides  of  which  consist  of  extremely  thin  and  delicate 
membranes. 

In  the  more  highly  organized  animals,  the  vital  fluid  is  distributed  through 
appropriate  channels  by  the  action  of  the  heart,  throughout  every  part  of  the 
body.  Near  the  heart  these  conduits  are  large,  and  few  in  number,  but  decrease 
in  size  and  become  less  numerous  as  they  are  more  remotely  situated.  In  plants 
no  such  central  fountain  exists,  but  the  fluids  necessary  for  their  life  and  devel- 
opment, entering  from  the  soil  through  countless  mouths  at  the  roots,  flow 
upward  along  the  minute  tubes  of  the  plants,  and  are  disseminated  to  every 
part  where  their  presence  is  needed.  The  form  of  these  tubes  is  generally 
cylindrical,  and  much  difference  exists  in  respect  to  their  size.  On  account  of 
the  great  minuteness  of  these  pores  it  is  extremely  difficult  to  estimate  their 
number  correctly.  An  approximation  to  the  truth  may,  however,  be  attained  by 
first  driving  off  the  fluid  that  fills  the  pores,  without  destroying  their  figure,  as 
is  done  in  the  preparation  of  charcoal,  and  then  examining  a  cross  section 
with  a  microscope.  This  method  was  pursued  by  Hooke,  who  numbered  in  a 


OF  THE  STRUCTURE  OF  WOOD  AND  HERBS.  79 

line,  the  eighteenth  of  an  inch  in  length,  no  less  than  one  hundred  and  fifty 
tubes.  In  an  inch  long  there  would  consequently  be  (18X150)  twenty-seven 
hundred  tubes,  and  in  a  square  inch  (2700  X  2700)  seven  millions  two  hun- 
dred and  ninety  thousand  tubes.  The  examinations  of  decayed  wood,  where 
the  tubes  were  empty,  led  to  the  same  result ;  and  further  corroboration  was 
obtained  by  Dr.  Hooke  from  the  inspection  of*  petrified  wood,  where  the 
situation  of  the  pores  was  very  conspicuous.  In  woods  that  are  remarka- 
ble for  their  compactness  and  density,  the  vessels  or  tubes  are  still  smaller  and 
more  numerous  within  a  given  space.  The  largest  tube  observed  by  Hedwig, 
in  the  stem  of  the  gourd,  possessed  an  apparent  size  of  one-twelfth  of  an  inch, 
when  seen  through  a  microscope  that  magnified  two  hundred  and  ninety  times. 
Its  real  diameter  was  therefore  one-twelfth  of  an  inch,  diminished  two  hundred 
and  ninety  times :  or  the  three  thousand  four  hundred  and  eightieth  part  of  an 
inch.  If,  therefore,  within  the  extent  of  a  square  inch  a  collection  of  tubes  like 
these  occupied  but  one  half  of  the  space,  no  less  a  number  than  six  millions 
fifty-five  thousand  two  hundred  would  be  comprised  within  this  small  compass. 

ARRANGEMENT. — These  tubes  are  not  arranged  singly  throughout  the  trunks 
and  branches,  but  are  collected  into  small  bundles  ;  in  the  stems  of  herbs  and 
of  roots,  each  small  bundle  is  composed  of  from  thirty  to  one  hundred  tubes,  and 
sometimes  of  many  hundreds.  In  herbs  the  bundles  are  often  placed  at  conside- 
rable distances  from  each  other  without  any  symmetrical  arrangement,  while  in 
trees  they  are  regularly  disposed  in  concentric  circles  ;  and,  when  cross  sections 
of  wood  are  viewed  through  a  microscope,  are  seen  distinctly  arranged  in  a  great 
variety  of  the  most  beautiful  and  elegant  figures.  It  was  supposed  by  the 
earlier  writers  on  vegetable  anatomy,  that  the  tubes  which  have  just  been  de- 
scribed were  of  two  kinds  ;  the  office  of  the  first  class  being  to  convey  sap,  and 
that  of  the  second  to  carry  air  to  the  different  parts  of  the  plant.  The  tubes 
were  thence  denominated  sap-vessels  and  air-vessels  ;  the  latter  class  also  receiv- 
ed the  name  of  spiral  vessels,  from  the  peculiar  manner  in  which  the  tube  is 
formed.  It  is  now  however  believed  by  distinguished  naturalists,  that  there  are 
no  vessels  exclusively  employed  for  the  conveyance  of  air,  but  that  all  the  tubes 
found  in  the  woody  parts  of  plants  are  sap-vessels  of  one  kind  only,  and  that  in 
different  plants,  and  in  different  circumstances  and  conditions  of  vegetation, 
these  vessels  or  tubes  are  capable  of  assuming  various  forms,  sizes,  and  character- 
istics ;  a  circumstance  which  has  led  many  observers  to  the  belief,  that  they  con- 
stituted several  distinct  species,  which  subserved  different  purposes  conducive  to 
the  life  and  growth  of  the  plant. 

In  figures  117,  118,  119,  120,  121,  and  122,  is  delineated  thesap-tube,  under 
the  several  forms  which  at  times  it  assumes.  In  figure  117,  it  appears  to  be 
covered  with  rows  of  small  projecting  knots.  Stripes  cross  it  in  figure  118; 
while  in  figures  119  and  120,  the  spiral  structure  is  distinctly  seen,  the  tube  being 
formed  in  the  same  way  as  a  paper-lighter  is  made,  by  rolling  a  long  and  nar- 
row surface  spirally  upon  itself.  In  figure  121,  the  vessel  appears  to  consist  of  a 


80  VIEWS    OF    THE    MICROSCOPIC    WORLD. 

Fig  117.       Fig.  118.  Fig.  122. 


Fig.  119.       Fig.  120.          Fig.  121. 

series  of  cups  or  beads  strung  together,  the  surface  of  the  several  parts  being 
studded  with  minute  projections.  The  spiral  structure  is  again  seen  in  the  122d 
figure,  and  the  characteristics  of  figures  117,  118,  and  121,  are  here  likewise 
recognised. 

CELLULAR  TISSUE. — The  tubes  just  described  are  bound  together  by  a  tissue 
filled  with  minute  cells,  which  has  thence  been  denominated  the  cellular  tissue. 
It  is  a  constituent  part  of  every  organ  of  the  more  perfect  plants,  and  in  many 
herbs  forms  the  principal  portion  of  their  substance ;  while  the  lower  order  of 
vegetables,  as  mosses,  mushrooms,  &c.,  are  said  to  consist  of  it  entirely. 

The  appearance  which  this  tissue  presents  is  extremely  diversified.  At  one 
time  it  is  seen  to  be  of  a  loose,  porous  texture,  every  part  of  which  is  transparent 
and  succulent.  Under  other  circumstances,  it  meets  the  eye  in  the  condition 
of  a  solid  body,  the  cells  being  so  closely  pressed  together  that  the  peculiarity 
of  its  structure  is  almost  lost.  In  a  third  case  the  cells  likewise  vanish  from  an- 
other cause,  for  the  tissue  then  spreads  out  into  a  membrane  so  extremely  deli- 
cate and  thin  that  all  traces  of  their  existence  disappear.  The  cells  or  cavities 
of  the  cellular  tissue  are  generally  arranged  in  a  direction  opposite  to  that  of  the 
tubes  of  the  vascular  system,  and  are  therefore  displayed  in  the  longitudinal 
and  not  in  the  cross  section  of  a  plant. 

The  forms  of  the  cells  are  exceedingly  various.  In  some  plants  they  are  of  a 
globular  shape,  in  others  angular,  but  differing  as  to  the  number  of  sides ;  seve- 
ral kinds  being  triangular,  others  square,  but  the  greater  proportion  exhibit  hex- 
agonal or  six-sided  figures. 


OF    THE    STRUCTURE    OF    WOOD    AND    HERBS. 


81 


Fig.  123 


Fig.  124. 


In  figure  123,  is  shown,  drawn  from  nature,  a  trans- 
verse slice  of  the  cellular  tissue  of  a  sugar-cane,  so  thin  as  to 
display  only  one  layer  of  cells,  but  a  thicker  slice  of  the  same 
plant  exhibits  a  second  set  of  cells  behind  the  first. 

These  cells  vary  greatly  in  respect  to  magnitude,  and  are 
represented  by  one  naturalist 
as  possessing  twenty  different 
sizes,  ranging  from  those  as 
large  as  a  pea  to  others  which 
are  so  minute  as  to  require  the 

aid  of  powerful  microscopes  to  perceive  them  dis- 
tinctly. 

Hooke  examined  a  thin  section  of  cork,  and  found 

that  no  less  than  sixty  cells  were  placed  endwise 

in  a  line  the  eighteenth  part  of  an  inch  in  length ; 

more  than  a  million  would  therefore  be  comprised 

within  the  surface  of  a  square  inch. 

In  most  plants  the  pores  of  the  cellular  tissue 

are  readily  discerned,  but  in  cork  they  require  to 

be  highly  magnified  in  order  to  be  clearly  seen. 

A  thin  slice  of  cork  thus  magnified  is  delineated  in 

figure  124.     The  substance  is  seen  to  consist  of  an  assemblage  of  minute  cells 

formed  of  extremely  thin  membrane.     The  average  size  of  the  cell  is  about  the 

eight  hundred  and  thirtieth  part  of  an  inch  in  diameter. 

PITH. — When  a  cross  section  of  a  tree  or  plant  is  viewed  by  the  naked  eye, 
it  is  seen  to  consist  of  three  parts,  the  pith,  the  woody  texture,  and  the  bark. 
The  size  of  the  pith  varies  in  different  trees,  in  some  being  from  two  to  three 
inches  in  diameter,  and  in  others  from  five  to  six ;  and  of  all  plants,  herbs  and 
shrubs  have  the  greatest  quantity  of  pith  in  proportion  to  the  other  parts.  The 
pith  is  found  to  consist  entirely  of  cellular  tissue,  and  the  cells  are  of  various 
sizes.  Those  of  the  thistle  appear  under  the  microscope  as  large  as  the  cells  of 
a  honey-comb ;  those  of  plum,  wormwood,  and  sumach,  are  smaller,  and  the 
cells  in  the  pith  of  the  apple  and  pear  are  still  less ;  while  those  of  the  oak  are  so 
minute  that  one  hundred  only  equal  in  size  a  single  cell  of  the  pith  of  the  thistle. 
The  size  of  the  cells  is  not  proportioned  to  that  of  the  pith,  for  in  the  plum,  the 
pith  of  which  is  less  than  that  of  the  pear,  the  cells  are  from  four  to  five  times  as 
large ;  and  the  cells  of  the  pith  of  the  hazel,  which  is  three  times  smaller  than 
that  of  the  holly,  are  ten  times  greater  than  those  in  the  holly. 

WOOD  AND  WOODY  TEXTURE. — The  second  portion  of  the  plant  is  the  wood 
or  woody  texture ;  it  encircles  the  pith,  and  consists,  as  already  stated,  of  two 
parts ;  bundles  of  tubes,  bound  together  by  cellular  tissue.  In  most  trees  the 
vessels  are  numerous,  and  when  beheld  in  a  cross  section  are  seen  to  be  disposed 

6 


82 


VIEWS    OF    THE    MICROSCOPIC    WORLD. 


Fig.  125. 


around  the  pith  in  concentric  layers,  and  rays  of  cellular  tissue  to  run  from  the 
pith  to  the  bark,  diverging  like  the  spokes  of  a  wheel  from  the  axle.  This  arrange- 
ment is  seen  in  drawing  134,  which  represents  a  cross  section  of  part  of  an 
ash  branch  three  years  old.  The  numerous  vessels  of  the  wood,  which  are  de- 
noted by  small  circles,  are  here  seen  occupying  the  space  D  C  I  K;  from  the 
pith  I  K  L  to  the  bark  A  B  C  D  ;  and  the  insertions  of  the  cellular  tissue  are  indi- 
cated by  the  lines  that  run  from  the  pith  outward  like  the  sticks  of  a  fan.  These 
insertions  of  tissue  pass  through  the  substance  of  the  wood,  and  are  much  diver- 
sified in  size  in  different  woods.  In  pine  they  are  of  a  medium  size,  and  in  pear 
and  holly  extremely  small,  but  no  uniformity  in  this  respect  is  observed  in  the 
same  wood,  for  in  holly,  hazel,  pear,  plum,  and  oak,  they 
are  very  unequal ;  some  in  the  holly  being  four  or  five 
times  thicker  than  the  rest;  while  in  the  plum  many  are 
six  or  seven  times  greater  than  others,  and  in  the  oak  ten 
times  at  the  least.  In  trees  like  the  palm,  the  vessels  of  the 
vascular  system  are  by  no  means  so  numerous  as  in  other 
woods,  and  being  necessarily  placed  at  a  greater  distance 
from  each  other,  do  not  present  that  symmetrical  radi- 
ated appearance  which  sections  of  common  trees  exhibit; 
but  the  bundles  of  tubes  are  promiscuously  scattered  amid 
the  cellular  tissue.  This  is  evident  from  a  glance  at  figure 
125,  which  represents  a  cross  section  of  the  palm,  the  dark 
spots  indicating  the  position  of  the  vessels,  and  the  lighter 
the  cellular  tissue.  In  the  case  of  herbs,  to  a  great  extent, 
the  cellular  tissue  forms  the  chief  portion  of  the  plant,  and 
the  vessels  of  the  vascular  system  are  but  few  in  number. 
When  a  cross  section  is  viewed  they  are  seen  in  bundles  dis- 
persed through  the  cellular  tissue,  at  considerable  distances 
from  each  other ;  they  are,  however,  symmetrically  ar 
ranged,  and  in  the  same  species  of  plant  always  maintain 
the  same  position  ;  the  vessels  being  situated  at  the  same  relative  distance  from 
each  other  and  from  the  centre  of  the  pith. 

BARK. — This  envelope,  which  encircles  the  wood,  is  composed  of  two  parts,  the 
true  bark  and  the  outer  skin  which  covers  it;  both  of  which  are  made  up  of  ves- 
sels and  cellular  tissue  like  the  wood.  The  tubes  or  vessels  belonging  to  the 
bark  are  denominated  proper  vessels,  and  are  filled  with  the  fluids  peculiar  to  this 
portion  of  the  plant.  In  some  herbs  these  vessels  often  cluster  together  in  separate 
columns,  and  are  arranged  in  a  circular  form ;  in  others  they  present  a  radiated 
appearance.  In  trees,  the  tubes  are  more  distinct,  and  assume  a  greater  regu- 
larity in  their  disposition. 

They  are  usually  found  near  the  inner  margin  of  the  bark,  next  to  the  wood, 
and  when  viewed  in  the  direction  of  their  length,  present  an  appearance  like  net- 
work. In  the  bark  the  vessels  are  found  to  possess  different  sizes  as  well  as  in 


OF    THE    STRUCTURE    OF    WOOD     AND    HERBS.  83 

the  wood.  In  the  pine,  for  instance,  the  tubes  containing  the  turpentine  exceed 
the  common  sap-vessels  in  magnitude  by  three  or  four  hundred  times,  and  are 
surrounded  by  a  ring  of  smaller  tubes.  In  drawing  143,  the  proper  vessels  of  the 
bark  containing  the  milky  juice  of  the  sumach  are  arranged  in  arched  clusters, 
each  cluster  consisting  of  several  hundred  distinct  tubes,  and  so  small  are  these 
tubes  that  a  single  turpentine  vessel  of  the  pine  sometimes  vies  in  magnitude 
with  an  entire  arched  cluster  of  the  sumach. 

In  figure  126  the  vessels  of  a  certain  species  of  pine  are  Fj(r 

displayed,  where  the  large  turpentine  tubes  of  the  bark  are 
seen  encircled  by  a  ring  of  smaller  tubes;  the  woody  part  of 
the  tree  having  been  cut  away,  so  that  the  longitudinal  as 
well  as  the  transverse  structure  can  be  clearly  seen.  Dr. 
Hill  discovered  by  close  investigation,  that  each  of  these 
large  tubes  was  nothing  more  than  an  opening  in  a  bun- 
dle of  small  tubes,  and  he  remarks  "  that  if  we  conceive 
any  small  bundle  of  tubes  to  be  opened  in  its  centre,  and 
the  vessels  driven  every  way  outward  until  they  are  stop- 
ped by  the  substance  of  the  bark,  we  shall  have  an  idea  of  the  structure  of  this 
larger  vessel;  which  is  nothing  more  than  a  great  cylindrical  tube,  passing 
through  the  centre  of  a  bundle  of  smaller  ones."  This  structure  is  plainly  per- 
ceived in  the  figure. 

The  vessels  containing  the  fluids  peculiar  to  the  bark  are  often  found  dispersed 
through  the  wood  from  bark  to  the  pith.  Thus,  in  the  fir  and  pine,  the  turpen- 
tine and  gum-tubes  are  seen  in  the  wood,  arranged  in  a  circle  around  the  centre, 
in  nearly  the  same  way  as  the  sap- vessels.  These  vessels  are  regarded  by  na- 
turalists as  having  once  belonged  to  the  bark,  which,  changing  into  wood  by  the 
natural  growth  of  the  tree,  in  the  manner  soon  to  be  explained,  and  becoming 
encased  annually  in  successive  layers  of  wood,  was  gradually  removed  farther 
and  farther  from  the  exterior  surface  of  the  tree.  The  skin  or  rind  of  the  bark 
when  taken  from  young  shoots,  appears  in  most  cases  to  consist  of  a  single  layer, 
but  in  many  kinds  of  wood  it  is  found  to  be  complex;  as  in  the  case  of  the  white 
birch,  in  which  it  consists  of  distinct  layers  that  are  readily  separated  from  each 
other,  amounting  not  unfrequently  to  sixteen  or  eighteen  in  number. 

In  some  trees  the  layers  are  still  more  numerous,  for  Ulloa  speaks  of  a  tree 
in  Peru,  from  the  rind  of  which  he  peeled  off  no  less  than  one  hundred  and 
fifty  envelopes ;  when,  tired  of  his  task,  he  refrained  from  counting  the  remain- 
der, as  the  layers  he  had  detached  did  not  constitute  more  than  half  the  thick- 
ness of  the  rind. 

THE  MODE  OF  GROWTH  IN  THE  TRUNK  AND  BRANCHES  OF  TREES. — Commencing 
on  the  outside  of  the  tree,  the  exterior  covering  is  the  skin  or  rind,  consisting,  as 
has  already  been  stated,  of  several  distinct  layers.  Beneath  this  is  the  bark,  compo- 
sed of  cellular  tissue  and  bundles  of  tubes  or  vessels  running  longitudinally ;  and  at 
first  parallel  to  each  other.  When  a  cross  section  is  made  of  a  shoot  of  a  year  old, 


84  VIEWS    OF    THE    MICROSCOPIC    WORLD. 

only  a  single  ring  of  vessels,  or  cluster  of  vessels  arranged  in  a  circle,  is  found 
surrounding  the  wood,  and  this,  with  the  tissue  in  which  they  are  enveloped,  con- 
stitutes the  bark  of  the  plant.  During  the  second  year,  a  new  layer  of  bark  with 
its  vessels  and  tissue  grows  within  the  former,  and  next  to  the  wood ;  and  every 
successive  year  a  new  layer  of  bark  is  thus  added  :  the  entire  thickness  of  this 
envelope  being  constituted  of  a  series  of  layers,  increasing  in  number  from  within. 

Next  to  the  bark,  the  wood  is  found  consisting  likewise,  as  we  have  seen,  of 
vessels  and  cellular  tissue,  and  the  cross  section  of  a  plant  or  shoot  of  one 
year's  growth,  exhibits  the  wood  arranged  around  the  pith,  and  composed 
of  a  ring  of  vessels  banded  together  by  cellular  tissue.  The  growth  of  the  suc- 
ceeding year  gives  rise  to  a  new  ring  of  vessels  outside  of  the  first  ring,  and  be- 
yond this  second  ring,  a  third  circle  of  vessels  appears  during  the  third  year.  The 
wood  of  the  tree  therefore  increases  from  within  outwards,  in  a  direction  contrary 
to  the  growth  of  the  bark ;  and  consists  of  a  series  of  rings,  equal  in  number  to  the 
years  indicating  the  age  of  the  tree.  The  outer  ring  is  whiter  and  more  full  of 
sap  than  the  rest,  and  has  received  from  this  circumstance  the  name  of  sap-wood. 
In  the  last  annual  layer  of  wood  and  bark,  by  which  the  trunk  is  increased  in 
size,  the  sap-wood  and  new  bark  are  in  contact ;  but  the  layer  of  the  next  year 
pushes  up  between,  and  separates  them  by  its  entire  thickness.  Every  year  a 
new  layer  is  thus  interposed  in  the  midst  of  the  others,  the  last  formed  layers  of 
wood  and  bark  touching  each  other,  while  the  oldest  are  the  most  widely  sepa- 
rated ;  the  first  ring  of  wood  directly  enclosing  the  pith  and  the  first  envelope 
of  bark  constituting  the  outer  surface. 

The  layers  of  wood  annually  formed  are  not  simple  in  their  structure,  but  are 
each  composed  of  a  great  number  of  other  layers.  These  delicate  membranes 
can  be  distinctly  perceived  in  the  oak  by  the  aid  of  a  common  magnifying  glass, 
when  the  branch  or  shoot  is  cut  obliquely.  By  macerating  the  rings  of  wood  in 
water,  Du  Hamel  was  enabled  to  separate  an  annual  layer  into  a  vast  number  of 
primary  layers,  which  were  thinner  than  the  finest  paper ;  and  he  afterwards 
discovered  by  experiment  that  these  primary  layers,  constituting  any  annual  ring, 
were  formed  in.  succession,  during  the  period  of  growth  and  vegetation  in  the 
year  to  which  the  ring  belonged.  So  that  however  curious  it  may  seem,  it  is  still 
true,  that  not  only  does  the  relative  thickness  of  each  annual  ring  indicate  the 
comparative  fruitfulness  of  every  year  of  the  existence  of  the  tree,  but  each  of 
the  primary  layers  composing  the  several  rings  tells,  by  its  thickness,  of  the  com- 
parative vegetative  energy  of  each  week  and  day  of  the  particular  season  to 
which  it  belongs;  and  thus  every  tree  becomes  a  record  of  the  fertility  of  that 
period  of  time  during  which  it  lived  and  flourished.  The  branch  possesses 
exactly  the  same  structure  as  the  trunk. 

SECTIONS  OF  WOOD. 

THE  HOLLY. — In  drawing  127  is  displayed  a  magnified  cross  section  of  a 
holly  branch  of  three  year's  growth.  The  several  parts  constituting  the 


ISP  m. 


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:riitn  Lit.hr 


N  Y 


OF  THE  STRUCTURE  OF  WOOD  AND  HERBS.  So 

twig  are  here  distinctly  seen.  C  F  G  is  the  pith,  consisting  of  cellular 
tissue,  and  the  cells  are  evidently  much  larger  than  those  in  other  parts  of  the 
section.  The  wood  is  comprised  within  the  space  H  I  C  F,  and  the  numer- 
ous spiral  and  sap- vessels  which  traverse  it  are  represented  in  position  by  the 
circular  dots  with  which  this  space  is  filled.  Running  from  C  F  to  D  D  are  a 
great  number  of  lines,  some  broad  and  others  narrow,  which  divide  the  vessels 
from  each  other  ;  these  insertions  are  the  cellular  tissue  of  the  wood,  and  are 
regularly  arranged  around  the  pith.  Two  of  the  larger  insertions  are  shown  in  the 
figure.  The  first  annual  ring  of  wood  occupies  the  space  C  F  M  N,  the  second, 
M  N  K  L,  and  the  third  K  L  H  I.  The  bark  extends  in  thickness  from  A  to 
H,  and  consists  of  the  skin  A  B,  portion  of  a  ring  of  cellular  tissue  P  P,  and  a 
row  of  proper  vessels  H  I,  situated  in  the  inner  margin  of  the  bark.  The  space 
D  D  H  I  represents  the  sap-wood,  which  is  also  traversed  by  minute  insertions 
of  cellular  tissue  radiating  from  the  pith. 

PEAR  TREE. — In  drawing  128  is  presented  one-eighth  part  of  a  section  of  a 
branch  of  a  Pear  tree,  both  magnified  and  of  its  natural  size.  It  exhibits,  of 
course,  the  same  general  features  as  the  section  of  the  Holly,  but  varies  in  some 
particulars.  The  rows  of  vessels  stretching  out  from  the  pith  to  the  bark,  are 
less  broken  than  in  the  Holly,  and  the  rays  of  cellular  tissue  are  more  regularly 
arranged ;  branching  out  at  equal  distances  from  each  other,  and  presenting,  with 
the  numerous  vessels  dispersed  throughout  the  wood,  a  remarkably  elegant  figure. 
The  three  rings  of  the  true  wood  E  F  M  N,  M  N  K  L,  and  K  L  D  C,  denoting 
the  age  of  the  branch,  are  distinctly  marked  ;  and  beyond  them  the  sap-wood 
occupies  the  space  D  C  H  I.  The  bark  is  comprised  within  the  space  H  I  A  B, 
and  is  formed  of  the  minute  cells  of  the  cellular  tissue,  interspersed  with  numer- 
ous figures  of  an  oval  shape.  These  last  are  clusters  of  proper  vessels  of  the  bark, 
and  are  rounder  in  form,  and  more  numerous,  the  nearer  they  approach  the  wood. 

THE  HAZEL. — A  section  of  a  Hazel  branch,  when  magnified,  exhibits  a  figure 
of  exquisite  beauty  and  symmetry.  In  drawing  129,  an  eighth  part  of  an  entire 
cross  section  of  a  bough  three  years  old  is  faithfully  delineated.  The  bark,  which 
is  included  within  the  space  A  B  C  D,  is  enriched  with  clusters  of  vessels  of 
various  shapes  and  figures.  The  skin  of  the  bark  is  represented  by  the  ring  A 
B,  to  which  succeeds  a  broad  band  Q  Q,  consisting  of  the  cells  of  the  cellular 
tissue ;  within  this  band  is  another  ring  H  I,  composed  of  sap-vessels.  The 
space  H  I D  C,  is  filled  partly  with  cellular  tissue  and  partly  with  sap-vessels,  in 
pear-shaped  and  semi-oval  clusters,  alternating  with  each  other  at  equal  inter- 
vals. The  wood  extends  throughout  the  space  D  0  E  F,  and  is  divided  into 
regular  and  equal  compartments  by  great  radial  insertions  of  cellular  tissue;  and 
these  compartments  are  still  further  subdivided  by  more  delicate  and  minute  rays 
of  tissue  running  from  the  pith  to  the  bark.  Throughout  the  wood  spiral 
vessels  are  profusely  scattered,  and  are  found  to  be  most  numerous  near  the 
bark,  or  in  the  growth  of  the  last  year,  D  C  K  L.  The  growth  of  the  second 


66  VIEWS    OF    THE    MICROSCOPIC    WORLD. 

year  is  comprised  within  the  space  K  L  M  N;  while  that  of  the  third  year  is 
represented  by  the  space  M  N  E  F.  The  size  of  the  pith,  E  F  G,  is  small  com- 
pared with  that  of  the  wood  ;  but  its  cells  a-re  much  larger  that  those  belonging 
to  the  pith  of  the  Holly.  The  small  figure  at  the  bottom  of  the  plate  repre- 
sents the  large  section  of  its  natural  size. 

ENGLISH  OAK. — A  section  of  Oak  of  three  years'  growth  is  exhibited  in  draw- 
ing 130,  varying  in  some  respects  from  the  several  kinds  of  woods  which  have 
already  been  described.  It  will  be  readily  seen  that  the  vessels  of  the  bark  are 
here  arranged  in  different  ways.  Through  the  middle  of  the  bark  an  unbroken 
arched  baud  of  vessels  extends  from  K  to  I,  while  a  row  of  large  oval  clusters, 
standing  at  equal  distances  from  each  other,  stretch  from  K  to  L,  next  to  the 
wood.  The  vessels  of  this  inner  row  are  of  a  peculiar  nature,  and  are  termed 
by  Grew  resiniferous  vessels,  since  they  contain  a  thick  juice  of  the  Oak  which  is 
not  sap,  but  bears  the  same  relation  to  it  in  the  Oak  as  the  turpentine  of  the 
Pine  to  the  sap  of  that  tree.  The  divisions  of  the  annual  rings  of  wood  are 
indicated  by  the  positions  of  the  arched  lines  of  larger  vessels,  extending  from 
M  to  N  and  from  O  to  P.  The  first  year's  growth  being  comprised  within  the 
space  E  F  0  P,  the  second  within  .that  of  O  P  M  N,  and  the  third  within  the 
area  M  N  D  C.  The  pith  occupies  the  space  E  F  G.  The  rays  of  cellular  tissue, 
diverging  from  the  centre  to  the  bark,  are  seen  in  this  tree  to  be  divided  into 
two  kinds  as  regards  size.  The  first  are  broad  insertions ;  which,  for  the  most 
part,  are  of  the  same  size,  and  are  disposed  around  the  centre  at  regular  inter- 
vals ;  the  second  are  the  finer  radial  divisions,  which  in  like  manner  are  uni- 
formly arranged  and  occupy  the  spaces  between  those  of  the  first  class. 

A  peculiarity  of  structure  belongs  to  the  Oak  and  some  other  trees,  which  is 
revealed  in  this  section.  By  comparing  this  figure  with  that  of  the  Pear,  for 
example,  all  the  dividing  lines  of*the  latter  are  seen  proceeding  from  the  centre, 
but  in  this,  numerous  white  waving  lines  are  discerned  running  across  the  radial 
divisions.  These  undulating  rings  constitute,  in  a  great  measure,  the  beauty 
of  the  Oak,  and  are  considered  by  Grew  as  sap-vessels,  which  once  existed  in  the 
bark,  but  in  process  of  time  became  condensed  and  hardened  into  wood. 

WHITE  OAK. — A  section  of  the  common  White  Oak,  magnified  one  hundred 
and  thirty  seven  times,  is  delineated  in  figure  131.  The  broad  band  a  a  is  one 
of  the  insertions  of  cellular  tissue  radiating  from  the  pith  ;  it  is  exceedingly 
compact,  for  no  pores  can  be  detected  within  it  when  subjected  to  this  high 
magnifying  power.  Narrower  insertions  of  cellular  tissue  b  6,  &c.,  traverse  the 
wood  in  the  same  direction  in  irregular  waving  lines.  The  spiral  vessels  d  c,  &c. 
are  scattered  in  considerable  numbers  throughout  the  wood,  occupying  a  large  pro- 
portion of  its  space.  They  vary  much  in  size,  the  smallest,  as  d  for  instance,  not 
being  more  than  one/owr  hundredth  of  an  inch  is  diameter  ;  while  one  of  the 
largest,  as  c,  measures  not  less  than  the  eighteenth  part  of  an  inch  across  it. 

Two  sets  of  these  large  spiral  vessels  are  seen  in  the  figure,  which,  like  those 


F 


OF     THE     STRUCTURE    OF    WOOD    AND    HERBS. 


87 


beheld  in  the  section  of  the  English  Oak,  are  arranged  along  the  inner  margin  of 
each  annual  ring  of  wood;  the  distance  between  the  two  clusters  being  the  thick- 
ness of  one  years  growth  of  wood.  The  wood  itself  appears  like  lace- work,  being 
filled  with  minute  pores,  varying  in  diameter  from  one  twelve  hundred  and 
fiftieth  part  of  an  inch  to  one  twenty-five  hundredth. 


Fig.  131. 


88  VIEWS    OF    THE     MICROSCOPIC    WORLD. 

ELM. — The  section  of  an  Elm  branch  which  appears  in  drawing  132,  is  an  ex- 
ceeding rich  figure,  and  the  several  divisions  are  boldly  defined.  The  skin  of 
the  bark  A  B  possesses  considerable  thickness,  and  the  pores  of  the  cellular 
tissue  belonging  to  this  integument,  are  exceedingly  small. 

Throughout  the  bark  bundles  of  the  proper  vessels  are  seen  profusely  scattered 
in  oval  or  egg-shaped  clusters,  and  beyond  it  the  sap-wood,  comprising  the 
space  DOTS.  The  whole  of  the  true  wood  is  included  in  the  space  D  C  E  F, 
and  is  the  growth  of  four  years  and  a  half.  The  annual  rings  are  very  distinctly 
marked ;  the  first  extending  from  E  to  Q,  the  second  from  Q  to  O,  the  third 
from  O  to  M,  and  the  fourth  from  M  to  K  ;  while  the  remaining  half  year's 
growth  occupies  the  space  K  L  D  C.  The  vessels  dispersed  through  the  wood 
differ  very  much  in  size  ;  the  larger,  disposed  in  circular  bands,  are  arranged  on 
the  inner  margin  of  every  annual  ring,  occupying  the  positions  Q  R,  O  P,  and  M  N, 
K  L  ;  while  others  are  scattered  promiscuously  throughout  the  wood,  and  are 
more  numerous  near  the  centre  of  the  section  than  in  the  more  recently  formed 
wood  towards  the  margin.  The  more  minute  vessels  are  seen  stretching  in  deli- 
cate and  broken  chains  across  the  rays  of  cellular  tissue,  emanating  from  the 
centre  ;  the  various  positions  of  the  rays  being  indicated  by  the  white  lines  in 
the  figure  running  from  the  pith  E  G  F,  and  penetrating  for  some  distance  into 
the  bark.  The  rays  of  cellular  tissue  possess  great  uniformity  in  their  respect- 
ive thicknesses,  as  well  as  in  the  intervals  by  which  they  are  separated  from  one 
another.  The  rays  are  usually  arranged  at  equal  distances  from  each  other. 

ENGLISH  WALNUT. — In  drawing  133  is  displayed  a  magnified  section  of  a  branch 
of  English  Walnut,  four  years  old,  and  which  presents  a  most  beautiful  configura- 
tion. A  B  indicates  the  position  of  the  skin  of  the  bark,  and  the  latter  envelope, 
with  its  cellular  tissue,  and  proper  ^essels,  is  comprised  within  the  space  A  B  C  D. 
The  proper  vessels  collected  together  in  round  clusters  are  distributed  in  two 
circular  rows  H  I  and  R  S,  deeply  situated  within  the  bark.  The  wood  is  in- 
cluded in  the  space  D  C  E  F.  The  first  annual  ring  extending  from  E  to  O,  the 
second  from  O  to  M,  the -third  from  M  to  K,  and  the  fourth,  including  the  ring  of 
sap-wood,  P  D,  from  K  to  D.  The  sap-vessels  distributed  through  the  wood 
are  not  numerous,  but  their  size  is  comparatively  great,  and,  as  in  the  Elm,  they 
are  grouped  more  thickly  together  near  the  pith,  the  cells  of  which  are  quite 
large  compared  with  those  of  the  pith  of  the  Elfn.  The  pith  itself  is  also  much 
larger  than  in  many  other  woods  of  the  same  age.  The  radial  lines  of 
cellular  tissue  in  the  Walnut  observe  no  uniformity  in  respect  to  their  relative 
thickness,  as  is  the  case  of  the  Elm,  neither  are  they  arranged  at  equal  distances 
from  each  other. 

But  the  most  remarkable  peculiarity  in  the  Walnut  is  the  broad  lohite  arched 
bands,  running  across  the  rays  of  cellular  tissue,  four  of  which  are  exhibited  in 
the  figure  before  us  ;  in  the  Elm  they  are  also  seen  disposed  in  a  similar  manner 
but  much  narrower.  Their  existence  is  attributed  to  the  same  circumstances 
that  cause  a  similar  appearance  in  the  Oak  ;  namely,  the  greater  compression  of 
the  cellular  tissue  where  these  bands  occur  than  in  other  portions  of  the  wood. 


Aderman  Lif.hr.^/.Q  Rma^ ,.,,.,  v  v 


OF    THE    STRUCTURE    OF    WOOD    AND    HERBS. 


89 


ASH  BRANCH. — In  drawing  134  is  delineated  a  cross  section  of  part  of  an  Ash 
branch,  three  years  old,  as  it  appears  when  magnified  to  a  considerable  extent. 
The  skin  of  the  bark  is  represented  in  position  by  the  circular  line  A  B.  The 
bark  comprises  the  space  A  B  C  D,  and  is  seen  to  consist  of  an  infinite  number  of 
cells  formed  by  the  cellular  tissue.  Within  the  bark,  next  to  the  skin  and 
nearest  to  the  wood,  clusters  of  minute  vessels  are  seen  extending  in  two  circu- 
lar rows  from  side  to  side.  The  pith,  composed  of  large  cells,  occupies  the 
space  I  L  K,  and  the  wood  the  remaining  portion  of  the  figure.  The  arrange- 
ment of  the  radial  insertions  of  cellular  tissue  is  very  beautiful ;  the  rays 
diverging  from  the  pith  to  the  bark  at  equal  distances  from  each  other,  and 
maintaining,  nearly  always,  the  same  size.  The  position  of  the  large  spiral  vessels 
in  the  wood  is  very  distinctly  marked,  gathering  in  arched  bands  near  two  divisions 
of  the  annual  growth.  These  divisions  are  seen  extending  from  H  to  G  and  from 
F  to  E.  The  small  figure  in  the  plate  is  the  natural  size  of  the  magnified  section. 

MAPLE. — A  cross  section  of  the  firm  wood  of  the  Maple  is  presented  in  fig- 
ure 135,  highly  magnified.  The  strong  dark  lines  are  the  rays  of  cellular  tissue, 

Fig.  135. 


emanating  from  the  ce'ntre  of  the  trunk  of  which  this  section  represents  a  part. 
The  large  oval  openings  are  sections  of  the  spiral  vessels  which  run  lengthwise 
through  the  trunk,  and  the  rest  of  the  figure  shows  the  true  wood  filled  with 
minute  pores,  whose  size  does  not  exceed  the  actual  measurement  of  one  twelve 
hundredth  of  an  inch  in  diameter. 

DOGWOOD. — A  magnified  cross  section  of  Dogwood  is  delineated  in  figure 
136.  This  wood  is  very  hard  and  firm  in  its  texture,  and  the  smaller  pores  are 
much  more  minute  than  those  of  the  maple  and  other  lighter  woods.  In  the 
specimen  exhibited,  a  multitude  of  fine  oval  pores  are  seen  scattered  throughout 
the  wood,  the  largest  of  which  does  not  exceed  one  two-thousandth  of  an  inch 
in  diameter,  and  the  smallest  is  not  more  than  one  three-thousandth  of  an  inch. 


90 


VIEWS    OF    THE    MICROSCOPIC    WORLD. 


The  large  openings  y  y,  &c.,  are  spiral  vessels,  having  a  diameter  of  about  one 
two  hundred  and  fiftieth  part  of  an  inch.  The  heavy  and  boldly  defined  lines 
running  lengthwise  of  the  figure  are  the  rays  of  cellular  tissue  which  proceed 
from  the  pith  to  the  bark. 

Fig.  136. 


WHITE  PINE. — A  transverse  section  of  White  Pine,  magnified  four  hundred 
times,  is  presented  in  figure  137.     The  cause  of  the  lightness  of  the  Pine  is  seen 


Fig.  137. 


at  <i  glance ;  for  the  wood  is  as  full  of  openings  as  apiece  of  lace-work,  and  con- 
sists of  nothing  but  a  web  woven -of  the  fine  fibres  of  the  cellular  tissue.  Across 
the  figure  at  the  points  a  a,  bands  of  cellular  tissue  are  beheld,  stretching  from 
side  to  side,  and  the  structure  is  here  more  compact  than  in  any  other  part  of 
the  wood.  These  divisions  are  portions  of  concentric  annual  layers  formed  by 
the  compression  of  the  cellular  tissue. 


OF    THE    STRUCTURE    OF    WOOD    AND    HERBS. 
Fig.  138. 


91 


A  longitudinal  section  of  the  same  tree  is  delineated  in  figure  138,  as  it  ap- 
pears when  magnified  likewise  four  hundred  times.  The  structure  is  exquisitely 
beautiful :  the  straight  lines  a  a,  b  6,  c  c,  d  d,  &c.,  are  sections  of  the  sides  of 
the  vessels  or  tubes  which  run  lengthwise  of  the  trunk,  the  ends  of  which  are 
disclosed  in  the  woven  lines  of  the  last  figure.  The  sides  of  the  vessels  are  seen 
studded  with  rows  of  small  circular  disks  which  have  received  the  name  of 
glands ;  each  disk  having  a  small  circular  ring  around  its  central  point.  The  form 
of  the  disk  is  not  always  the  same  ;  it  is  generally  circular  but  frequently  oval ; 
and  when  closely  arranged  together  they  assume  an  angular  shape.  In  some 
species  of  Pines  the  disks  run  through  the  vessels  in  singTe  rows  ;  but  in  others, 
as  in  the  case  of  the  White  Pine,  they  occur,  as  is  obvious,  both  in  single  and 
double  rows.  It  is  a  remarkable  fact,  that  throughout  the  entire  genus  of  the 
living,  true  Pines,  no  more  than  two  rows  of  disks  are  ever  found  in  the  longitu- 
dinal section  of  a  single  vessel,  and  that  when  a  double  row  occurs,  the  corres- 
ponding disks  of  each  row  are  placed  side  by  side.  The  vessels  are  sometimes 
found  without  disks. 

A  class  of  cone-bearing  trees,  allied  to  the  Pines,  is  known  by  the  name  of 
Araucaria.  It  includes  some  of  the  loftiest  living  trees,  and  the  well-known 
species  that  grows  in  Norfolk  Island,  near  New  South  Wales;  and  which  bears 
the  name  of  the  Norfolk  Island  Pine.  This  class  possesses  certain  peculiarities 
of  structure  which  are  at  once  detected  by  the  microscope,  and  distinguish  it 
from  the  true  Pines. 

In  figure   139  a  longitudinal  section  of  the  Norfolk  Island  Pine  is  displayed, 
Fig.  139.  magnified  to  the  same  extent  as  the  two  preced- 

ing figures.  The  disks  that  cover  the  sides  of  the 
vessels  are  here  arranged  in  double  and  triple 
rows  ;  and  in  the  Araucarias  the  rows  belonging 
to  the  section  of  a  single  vessel  vary  in  number 
from  one  to  four. 

Another  peculiarity  is  also  perceived  in  the 
shape  of  the  disks,  which,  instead  of  being  gen- 
erally circular  like  those  of  the  pine,  are  for  the 
most  part  bounded  by  straight  lines.  The  disks 
also  of  both  the  rows  in  a  double  row,  are  not 


92 


VIEWS    OF    THE    MICROSCOPIC    WORLD. 


placed  side  by  side,  but  always  alternate  with  each  other.  The  first  disk  of  one  row, 
for  example,  being  placed  opposite  the  vacant  space  separating  the  first  and  second 
disks  of  the  adjoining  row.  The  disks  of  the  Araucarias  are  not  more  than  one 
half  the  size  of  those  belonging  to  the  real  pines,  and  are  so  numerous  that  Mr. 
Nicol  counted  as  many  as  fifty  in  a  row,  one-twentieth  of  an  inch  in  length. 
The  diameter  of  a  disk,  allowing  that  they  touched  each  other,  could  therefore 
not  exceed  the  thousandth  part  of  an  inch  ;  a  magnitude  of  vast  extent  com- 
pared with  the  thickness  of  those  infinitely  slender  fibres,  which,  woven  together 
into  an  exquisitely  delicate  tissue,  form  the  partitions  of  the  numerous  cells  of  the 
trunk. 

Fig.  140. 


OF    THE    STRUCTURE    OF    WOOD    AND    HERBS. 


93 


MALLACA. — A  portion  of  a  cross  section  of  a  species  of  Bamboo,  found  in  the 
Mallaca  isles,  from  whence  its  name  is  derived,  is  exhibited  in  figure  140,  mag- 
nified one  hundred  and  fifty  times.  The  five  large  rings  are  bundles  of  vessels 
running  lengthwise  through  the  trunk,  the  vessels  of  each  forming  by  their 
mutual  arrangement  five  tubes  (a  a  a  a  a)  of  considerable  size,  which  traverse 
the  bundles  through  the  centre  from  end  to  epd.  So  porous  is  the  stalk  of  the 
Mallaca,  that  by  applying  the  mouth  to  one  end  of  a  stem  several  feet  in  length, 
a  lighted  lamp  placed  at  the  other  extremity  can  almost  be  extinguished  by  the 
impulse  of  the  breath,  blown  through  the  stalk  ;  nor  is  this  surprising,  for  the 
large  vessels  (a  a  a  a  a)  are  one-seventieth  part  of  an  inch  in  diameter.  The 
vessels  composing  the  rings  are  evidently  far  inferior  in  size  to  the  tubes ;  and 
upon  actual  measurement  the  greatest  are  found  not  to  exceed  one-five-hun- 
dredth of  an  inch  in  diameter.  An  elaborate  net-work  of  cellular  tissue  (6  b) 
twines  around  and  among  th'e  cylindrical  clusters  of  vessels,  and  binds  them 
firmly  together  with  its  delicate  but  strong  cordage. 

In  figure  141  is  exhibited  a  drawing  of  a  cross  section  of  the  common  Larch, 

Fig.  141. 


94  VIEWS    OF    THE    MICROSCOPIC    WOKLD. 

greatly  magnified.  The  strong  lines  a  a  a  a  a  a  a,  are  the  rays  of  cellular  tissue 
which  proceed  from  the  centre  to  the  bark,  but  on  account  of  the  smallness 
of  the  sections  magnified,  their  divergence  from  each  other  is  too  small  to  be 
detected.  The  remaining  portions  of  the  wood  consist  of  a  perfect  chainwork 
of  cells,  formed  of  the  cellular  tissue.  These  cells  are  compressed,  like  those  of 
the  Oak,  at  regular  intervals,  as  shown  at  6  b  b  b  b  6,  in  directions  apparently  at 
right  angles  to  the  radial  insertions.  The  width  of  the  cells,  where  they 'are 
not  compressed,  is  about  the  twelve  hundred  and  fiftieth  part  of  an  inch,  and 
the  thickness  of  one  of  the  radial  insertions,  as  a  b  b  6,  is  a  little  less  than  the 
nineteen-hundredth  part  of  an  inch. 

WHITEWOOD. —  The  elegant  structure  of  a  transverse  section  of  Whitewood,  as 
revealed  by  the  microscope,  is  displayed  in  figure  142.     The  four  heavy  lines, 

Fip.  142. 


running  in  a  parallel  direction  with  each  other,  are  some  of  the  radial  in- 
sertions of  cellular  tissue,  and  in  thickness  do  not  exceed  one-twelve  hun- 
dredth part  of  an  inch. 

The  large  openings  scattered  throughout  the  wood  are  sections  of  the  spiral 
vessels,  the  diameters  of  which,  when  largest,  measure  only  the  three  hundredth 
part  of  an  inch.  The  rest  of  the  space  is  filled  with  a  most  exquisite  network 
of  fibres,  the  meshes  of  which  are  angular  in  form,  the  whole  surpassing  in 
the  delicacy  of  its  texture,  the  fabric  of  the  finest  laces. 

SUMACH. — A  singular  figure  is  exhibited  in  drawing  143,  which  represents  one 
eighth  part  of  a  cross  section  of  the  common  Sumach  of  one  year's  growth. 
The  bark  occupies  the  space  A  B  K  L,  the  pith  that  of  E  F  G,  while  the 
wood,  including  the  sap-wood  K  L  C  D,  is  comprised  within  the  limits  K  L  E  F. 
The  bark  is  covered  with  a  down  of  fine  hairs,  which  when  magnified,  fringe  the 
section  with  the  thorn-like  figures  a  a,  as  shown  in  the  drawing.  Most  ot 


14-5. 


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OF    THE    STRUCTURE    OF    WOOD    AND    HERBS.  95 

them  taper  to  a  point,  but  some  of  them,  as  is  seen,  are  rounded  and 
knobbed  at  the  end.  The  narrow  boundary  extending  from  A  to  13,  indicates 
the  position  of  the  skin  of  the  bark,  and  within  the  bark  itself  the  vessels  are  va- 
riously arranged.  In  the  band  just  below  A  B  they  are  small,  much  crowded  to- 
gether, and  very  compact ;  while  those  next  in  order  towards  the  centre  are 
larger.  Next  succeeds  a  row  of  vessels  in  arched  clusters,  extending  from  H  to  I, 
the  cells  being  exceedingly  small  and  crowded  together  by  hundreds  in  one  arch. 
Below  these  a  ring  of  large  tubes  are  seen  stretching  ovel*from  K  to  L.  This 
latter  class  are  termed  milk-vessels,  on  account  of  their  containing  a  milky  liquid 
peculiar  to  the  Sumach.  The  wood  below  D  C  is  filled  with  pores,  which  seem 
to  be  disposed  without  regard  to  any  particular  order  ;  but  the  radial  divisions 
of  cellular  tissue  evidently  tend  towards  a  regular  arrangement.  A  waving 
band  of  sap-vessels  extends  from  E  to  F,  bordering  the  edge  of  the  wood  where 
the  pith  commences. 

WORMWOOD. — In  drawing  144  is  presented  a  magnified  representation  of  an 
eighth  part  of  a  transverse  section  of  a  stalk  of  Wormwood.  It  is  a  structure  of 
extreme  regularity,  and  the  great  size  of  the  pith,  compared  with  that  of  the  wood, 
shows  at  a  glance  its  herbaceous  character.  The  bark  includes  the  whole  of 
the  surface  A  B  C  D,  the  wood  occupying  only  the  space  D  C  E  F,  while  the 
pith  comprises  all  the  rest  of  the  figure  as  lar  as  G.  The  spherical  cavities  of  the 
cellular  tissue  form  a  broad  ring  extending  in  thickness  from  A  to  H,  and  within 
this  space  a  number  of  large  vessels,  as  the  one  at  b,  are  situated ;  arranged  in  a 
circular  row  along  the  inner  margin  of  the  ring  of  cellular  tissue.  These  are 
termed  the  resiniferous  or  gum-vessels,  which  secrete  the  aromatic  fluid  peculiar 
to  the  plant.  Some  vessels  of  this  kind  are  also  found  within  the  pith,  two  of 
which  are  delineated  just  above  E  X  F.  The  semi-circular  figures  e  d  f,  &c.,  are 
clusters  of  sap-vessels,  and  span  the  sections  in  a  row  from  K  to  I.  Within  the 
woody  part  the  spiral  vessels  are  seen,  but  quite  thinly  and  irregularly  scattered. 
The  broad  insertions  in  the  woody  part,  and  which  diverge  from  each  other  as 
if  proceeding  from  the  centre,  are  the  rays  of  cellular  tissue,  which  in  this  plant 
are  seen  to  be  of  comparatively  great  thickness,  and  commence  and  terminate 
in  a  different  manner  from  the  same  rays  in  wood.  For  here,  instead  of  being 
distinct  lines,  they  are  beheld  arched  at  both  extremities  and  united  with  each 
other.  Moreover  they  do  not  terminate  where  the  wood  ends,  on  the  line  D  C, 
but  extend  nearly  half  their  length  into  the  bark,  enclosing  the  semi-circular 
clusters  of  sap-vessels.  The  pith,  as  is  evident,  is  very  porous,  consisting  of  a 
vast  number  of  large  cells. 

ROOT  OF  WORMWOOD. — The  structure  of  the  roots  of  plants  is  similar  to  that 
of  the  trunk,  being  formed  of  the  same  textures  disposed  in  a  corresponding 
manner.  Sections  of  roots  display  a  symmetry  and  elegance  of  arrangement  by 
no  means  inferior  to  that  revealed  in  transverse  slices  of  wood.  In  drawing  145 
is  delineated  a  cross  section  of  the  root  of  Wormwood  of  its  natural  size,  and  in 


96  VIEWS    OF    THE    MICROSCOPIC    WORLD. 

figure  146  a  quarter  section  of  the  same  is  exhibited  considerably  magnified.  ID 
the  magnified  figure,  the  area  A  A  B  B  indicates  the  space  occupied  by  the 
skin  of  the  bark,  while  the  bark,  consisting  of  cellular  tissue  and  vessels,  is  in- 
cluded within  the  limits  B  B  C  C.  The  large  circular  spots  interspersed  through 
the  bark  are  the  gum-vessels  of  the  Wormwood,  which  are  likewise  seen  in  the 
bark  of  the  stalk.  Radiating  from  the  centre  of  the  section,  and  dividing  it  into 
symmetrical  portions,  three  complete  figures  are  seen,  shaped  like  the  sticks  of 
an  ivory  fan,  traversing  the  wood  and  extending  into  the  bark.  These  figures 
terminate  in  the  bark  in  clusters  of  vessels,  through  which  flows  a  limpid  fluid 
or  sap  ;  and  within  these  clusters  one  or  more  gum-vessels  exists.  The  rest  of 
the  figure  comprises  the  woody  portion  of  the  root,  which  consists  of  two  parts  ; 
namely,  the  true  wood  E,  forming  the  lower  part  of  the  radial  figure  just  des- 
cribed ;  and  the  cellular  tissue,  D,  interposed  between  them,  and  running  from 
the  bark  to  the  very  centre  of  the  root.  Throughout  the  true  wood,  spiral  ves- 
sels are  scattered  which  increase  in  size  from  the  centre  outward.  A  section 
of  the  common  thistle  displays  great  beauty  in  the  formation  of  the  cavities 
of  the  cellular  tissue.  The  pith  consists  of  cells  of  different  sizes,  those  of 
the  largest  kind  being  one  hundred  times  greater  than  those  in  the  Oak. 
These  cells  are  not  spherical,  but  are  angular  cavities  of  a  regular  shape,  the 
sides  of  which  are  formed  of  fibres  running,  in  most  cases,  horizontally  and 
winding  in  a  circular  manner  out  of  one  cell  into  another  ;  a  single  ring  of  fibre 
passing  into  no  less  than  six  cells,  and  constituting  a  side  in  each.  Large  spiral 
vessels  are  distributed  throughout  the  woody  part,  which  is  separated  into  regu- 
lar oval-shaped  compartments  by  thick  divisions  of  cellular  tissue,  that  penetrate 
far  into  the  bark  ;  while  two  sets  of  vessels,  the  one  filled  with  a  milky  and  the 
other  with  a  limpid  fluid,  are  arranged  on  the  outer  verge  of  the  pith  in  a  double 
row  of  crescent-shaped  clusters. 

In  view  of  the  facts  just  adduced,  we  see  at  once  the  high  utility  of  the  micros- 
cope in  revealing  to  us  the  true  nature  of  the  structure  of  bodies.  Pores  or 
vacant  spaces  are  found  diffused  through  the  mass  of  bodies  to  such  an  extent, 
that  porosity  is  one  of  the  leading  mechanical  properties  of  matter ;  but  in  the 
denser  bodies  the  pores  cannot  be  distinguished  by  the  naked  eye.  And  the 
microscope  is  needed  to  render  them  clearly  visible.  Beneath  its  revealing 
glasses,  substances  which  before  appeared  solid,  are  now  seen,  perforated  with 
innumerable  cells,  which  in  the  case  of  woods,  occupy,  for  the  most  part,  more 
space  than  their  intersecting  sides  ;  and  even  the  apparently  solid  sides  of  the 
larger  cells  yield  to  the  higher  magnifying  powers,  and  display  a  porous  struc- 
ture. 

FOSSIL  WOODS  AND  PLANTS. 

Not  only  is  the  microscope  eminently  serviceable  to  the  botanist,  in  revealing 
the  curious  structures  of  living  plants  and  their  interior  organization,  but  it  is 
highly  useful  to  the  geologist,  who  is  enabled  by  its  aid  to  read  with  the  utmost 


N9146. 


OF   THE    STRUCTURE    OF   WOOD    AND    HERBS.  97 

precision  many  portions  of  the  ancient  vegetable  history  of  our  globe,  legibly 
imprinted  in  its  fossil  woods  and  plants.  So  perfectly  has  their  structure  been 
preserved  for  ages,  that  the  skilful  observer  easily  detects  the  various  species, 
and  assigns  them  their  appropriate  place  in  the  vegetable  kingdom.  The  sub- 
stance of  these  woods,  as  Mantell  remarks,  is  completely  permeated  by  mineral 
matter.  It  may  be  lime,  flint,  iron,  or  iron  united  with  sulphur ;  and  yet  both 
the  external  character  and  internal  structure  be  preserved.  Such  are  the  fossil 
trees  of  the  Isle  of  Portland,  where  a  whole  forest  of  Pines  seems  to  have  been 
transformed  into  stone,  on  the  very  spot  where  they  grew  and  flourished :  the 
roots  of  the  trunks  changed  into  flint,  piercing  deep  into  the  soil  whence  they 
sprung.  Fragments  of  these  trees  so  closely  resemble  decayed  wood,  that  a 
person  who  bestows  upon  them  only  a  casual  glance  is  completely  deceived  ; 
but,  by  close  examination  of  their  texture  and  substance,  he  finds  that  they  pos- 
sess the  weight  and  hardness  of  stone.  In  wood  petrified  by  flint  the  most 
delicate  tissues  of  the  original  remain  uninjured,  and  are  displayed  under  the  mi- 
croscope in  the  most  beautiful  and  distinct  manner.  Wood  petrified  by  lime 
also  retains  its  structure,  and  in  many  limestones  leaves  and  seed-vessels  are 
faithfully  preserved. 

In  the  Egyptian  and  Lybian  deserts,  a  numerous  assemblage  of  trees  has  been 
discovered,  petrified  by  flint.  Fragments  are  found  everywhere  scattered  over 
this  arid  region,  but  the  most  interesting  locality  is  a  table-land,  about  seven 
miles  south-east  of  Cairo,  where  the  trees  are  found  in  such  numbers  that  it  is 
termed  the  Petrified  forest.  Here  huge  trunks  of  flint  are  seen  crossing  each 
other  in  every  direction,  as  if  swept  down  by  the  irresistible  force  of  a  hurri- 
cane. 

Two  of  the  largest,  the  dimensions  of  which  were  taken  by  Col.  Head,  who 
visited  this  spot,  measured  respectively  forty-eight  and  sixty  feet  in  length,  and 
two  and  a  half  and  three  feet  in  diameter  at  the  base.  In  the  rich  specimens 
collected  by  him  from  this  locality,  the  most  delicate  cells  and  veins  of  the 
interior  stricture  of  the  wood  are  filled  with  chalcedony  and  jasper,  and  some 
of  the  vessels,  injected  with  flint  of  a  bright  vermilion  and  blue  color,  traverse 
the  cellular  tissue,  which  gleams  with  a  golden  hue. 

Not  only  on  the  surface  of  the  ground  are  petrified  trees  discovered,  but  they 
have  been  brought  to  the  light  from  a  depth  of  more  than  one  hundred  feet ; 
where,  notwithstanding  they  had  been  buried  for  ages,  their  structure  was  so 
perfect,  that  the  species  to  which  they  belonged  was  at  once  identified.  To 
effect  this  result  a  transverse  or  longitudinal  section  of  the  fossil  specimen  to  be 
examined  is  obtained,  which,  after  being  cemented  to  a  slip  of  glass,  with  Cana- 
dian balsam,  is  ground  down  with  emery,  until  it  becomes  sufficiently  thin  for 
its  structure  to  be  perceived  under  the  microscope.  When  the  section  is  thus 
properly  prepared,  and  magnified  from  one  to  four  hundred  times,  the  pecu- 
liarities in  the  structure  of  the  wood  are  revealed  with  great  distinctness. 

Four  specimens  of  fossil  woods  are  delineated  in  figures  147,  148,  149, 
and  150;  and  by  comparing  them  with  the  figures  137,  138,  and  139, 


98 


VIEWS    OF    THE    MICROSCOPIC    WORLD. 


Fig.  148. 


tan 


Fig.  150. 


their  identity  with  the  coniferous  woods  is  at  once  perceived.     Figure  147  is  a 
transverse  section  of  a  species  of  Pine,  petrified  by  flint,  Fi    147 

and  taken  from  a  quarry  near  Maids  tone  in  Kent.  It  is 
magnified  in  length  one  hundred  and  twenty  times,  and  is 
exhibited  as  it  appeared  when  viewed  by  reflected  light ; 
the  lighter  portions  representing  the  delicate  web  of  fibres 
constituting  the  wood.  A  longitudinal  section  of  the  same 
wood  is  shown  in  figure  148,  magnified  li- 
nearly two  hundred  and  fifty  times.  Sev- 
eral rows  of  parallel  vessels  are  revealed 
running  in  the  direction  of  the  trunk,  and  each,  like  the  White 
Pine,  is  studded  along  the  sides  with  F.  Mg 

single  rows  of  disks  or  glands.  Fig- 
ure 149  is  a  transverse  section  of  co- 
niferous wood,  petrified  by  lime.  It 
is  magnified  eighty  times,  and  exhibits  very  clearly 
the  cross  sections  of  numer- 
ous rows  of  transverse  ves- 
sels. Figure  150  is  a  lon- 
gitudinal section  of  the  same,  magnified  one  hun- 
dred and  twenty  times,  and  shows  with  great  dis- 
tinctness the  coniferous  nature  of  the  wood,  for  the 
double  rows  of  disks  alternating  with  each  other, 
are  seen  embossing  the  whole  range  of  the  parallel 
vessels.  Ferns  of  great  beauty  are  preserved  by 
petrifaction  in  the  same  manner.  In  the  vicinity  of 
Chemnitz  in  Saxony,  ferns  petrified  by  flint  are  found,  their  external  surface 
possessing  a  woody  appearance  of  a  reddish  brown  hue,  while  the  interior  struc- 
ture is  of  a  dull  red,  variegated  with  blue  and  yellow,  arising  from  the  agate  and 
chalcedony  which  occupies  the  most  minute  ramifications  of  the  vessels  of  the 
plant.  When  slices  of  the  fossil  are  ground  down  very  thin,  the  microscope  re- 
veals the  peculiar  structure  of  the  plant,  though  unnumbered  years  have  elapsed 
since  it  was  living,  with  as  much  faithfulness  as  the  organization  of  the  speci- 
men which  has  just  been  gathered  from  the  fields. 

Not  only  are  the  more  solid  and  durable  portions  of  wood  and  vegetables 
preserved  for  ages  by  petrifaction,  but  the  pollen  of  cone-bearing  trees,  like  the 
Pine,  has  been  found  in  a  fossil  state.  In  Egra,  in  Bohemia,  a  deposit  has  been 
discovered  two  miles  long  and  twenty-eight  feet  thick,  entirely  composed  of  fos- 
sil animalcules  and  pollen ;  the  first  ten  feet  being  marl  filled  with  Infusoria, 
and  the  remaining  eighteen,  pollen  mingled  with  fossil  animalcules. 

COAL. — It  has  been  proved  beyond  a  doubt  that  the  vast  stores  of  coal,  which 
have  been  provided  for  the  use  of  man,  are  of  vegetable  origin ;  and  the  micro- 
scope has  been  of  essential  use  in  enabling  the  investigator  to  detect  the  peculiar 


OP    THE    STRUCTURE    OF    WOOD    AND    HERBS.  99 

structure  of  the  plants  that  compose  it.  Mantell  thus  remarks : — "  The 
slaty  coal  generally  preserves  traces  of  the  cellular  tissue  and  spiral  vessels ;  and 
dotted  cells,  indicating  the  coniferous  structure,  may  readily  be  detected,  by  the 
aid  of  the  microscope,  in  chips  or  slices  prepared  in  a  proper  manner.  In  many 
examples  the  cells  are  filled  with  an  amber-colored,  resinous  substance ;  in  others 
the  organization  is  so  well  preserved,  that  on  the  surface,  exposed  by  cracking 
from  heat,  cellular  tissue,  spiral  vessels,  and  cells  studded  with  glands,  may  be 
detected.  Even  in  the  white  ashes  left  after  the  combustion  of  coal,  traces  of 
the  spiral  vessels  are  discernible,  with  a  high  magnifying  power.  Some  beds  of 
coal  appear  to  be  wholly  composed  of  minute  leaves  ;  for  if  a  mass  be  recently 
extracted  from  the  mine  and  split  asunder,  the  exposed  surfaces  are  found  cov- 
ered with  delicate  pellicles  of  carbonized  leaves  and  fibres  matted  together,  and 
flake  after  flake  may  be  peeled  through  a  thickness  of  many  inches,  and  the 
same  structure  be  still  apparent.  Rarely  are  any  large  trunks  and  branches  ob- 
servable in  the  coal,  but  the  appearance  is  that  of  an  immense  deposit  of  deli- 
cate  foliage." 


IOC  VIEWS    OF    THE    MICROSCOPIC    WORLD. 


CHAPTER   V. 

CRYSTALLIZATIONS. 

"  The  crystal  drops 
Shoot  into  pillars  of  pellucid  length, 
In  forms  so  various,  that  no  powers  of  art, 
The  pencil  or  the  pen,  may  trace  the  scene. 
Here  glittering  turrets  rise,  upbearing  high 
Large  growth  of  what  may  seem  the  sparkling  trees 
And  shrubs  of  fairy-land.     And  fretted  wild, 
The  growing  wonder  takes  a  thousand  shapes 
Capricious."  COWPER. 

ONE  of  the  most  beautiful  discoveries  of  science  is  that  which  reveals  the  sin- 
gular fact,  that  when  bodies  pass  from  the  liquid  to  the  solid  state,  with  a 
proper  degree  of  slowness,  they  assume  forms  peculiar  to  themselves,  which  are 
often  characterized  by  great  elegance  and  beauty.  These  configurations  are 
termed  crystallizations,  and  each  crystalline  substance  is  regarded  as  having  an 
original  form,  called  the  primitive  crystal ;  a  number  of  which,  combining  in 
various  ways,  frequently  give  rise  to  a  rich  assemblage  of  the  most  exquisite 
and  symmetrical  figures. 

The  greater  part  of  the  solid  bodies  that  compose  the  mineral  crust  of  the 
globe  are  discovered  in  a  crystallized  state.  This  is  true,  for  instance,  of  granite, 
which  consists  of  crystals  of  quartz,  feldspar,  and  mica ;  and  vast  hilly  ranges 
of  clay-slate  are  likewise  constituted  of  a  multitude  of  regular  forms.  The 
body  before  crystallization  may  exist  in  the  fluid  state,  either  from  combining 
with  a  liquid,  or  from  the  action  of  fire.  Brine  is  an  instance  of  the  first  condi- 
tion. Here  the  salt  is  thoroughly  dissolved,  so  that  a  particle  cannot  possibly 
be  seen ;  but  if  the  solution  is  slowly  evaporated,  the  salt  again  appears  in  the 
form  of  cubes.  An  example  of  the  second  mode  of  action  is  afforded  in  the 
case  of  sulphur,  which,  when  melted  and  suffered  to  cool  gradually,  shoots  out 
into  crystals,  which,  if  undisturbed,  are  soon  blended  into  a  compact  mass. 
The  original  atoms  are  so  inconceivably  small,  that  not  only  do  they  escape  the 
unaided  eye,  but  even  when  it  is  assisted  by  the  most  powerful  glasses  they  still 
elude  its  utmost  range.  Nevertheless,  when,  in  the  act  of  crystallization, 
particle  begins  to  unite  with  particle,  the  microscope  is  of  great  utility,  during 
the  earlier  stages  of  the  process,  and  crystals  of  the  richest  configuration  are 
then  seen  forming  immediately  under  the  eye,  branching  in  every  direction,  with 
the  most  wonderful  regularity  and  symmetry ;  and  often  bearing  a  striking  re- 
semblance to  the  most  beautiful  and  graceful  foliage,  or  crowding  together  iii 


N9151. 


m 


v:/* 

/ 


152,. 


CRYSTALLIZATIONS.  101 

glittering  star-like  clusters.  It  is  only  those  substances  which  crystallize  rapidly 
whose  beautiful  forming  figures  can  be  seen  by  the  microscope,  and  in  order  to 
render  them  visible,  the  following  process  is  employed : — The  salts  are  first  dis- 
solved in  water  until  the  liquid  is  thoroughly  saturated,  and  then,  when  it  is  de- 
sired to  view  the  crystallization,  a  drop  or  two  of  the  solution  is  spread  over  a 
clear  strip  of  glass,  which  has  been  previously  warmed.  The  watery  film  is  then 
placed  near  the  focus  of  the  object-glass  of  the  microscope,  and  if  the  solar 
microscope  is  employed,  a  large  image  of  the  liquid  on  the  glass  is  seen  upon 
the  screen.  As  soon  as  the  fluid  is  sufficiently  evaporated,  the  dissolved  salt 
is  beheld  changing  rapidly  from  the  fluid  to  the  solid  state,  and  branching  over 
the  whole  screen  in  crystals  of  the  most  exquisite  forms  ;  a  single  crystal,  in 
certain  cases,  often  apparently  shooting  the  length  of  six  or  eight  feet,  in  the 
course  of  half  a  minute.  In  the  present  chapter  we  shall  describe  some  of  the 
most  interesting  crystallizations. 

NITRATE  OF  POTASH,  OR  SALTPETRE. — When  this  salt  is  dissolved  in  water, 
and  a  few  drops  thinly  spread  over  a  glass  slide,  crystals  are  beheld  shooting  in- 
ward from  the  edges  of  the  fluid,  upon  the  application  of  a  gentle  heat.  The 
crystals  are  very  transparent,  and  their  primitive  form  is  that  of  six-sided  prisms.  In 
drawing  151  many  varieties  of  crystals  are  delineated,  as  they  appear  under 
the  microscope  in  a  crystallized  film,  moderately  magnified.  If  the  crystals 
form  with  great  rapidity,  long  arrow-headed  shafts,  like  that  portrayed  at  C, 
are  seen  shooting  swiftly  along  and  throwing  out  lateral  spurs  from  one  side, 
forming  a  figure  like  B.  These  lateral  branches  run  parallel  to  each  other,  and 
from  their  sides  secondary  branches  likewise  emanate,  spreading  over  the  sur- 
face in  lines  of  crystal  network.  If  the  process  of  crystallization  advances  with 
less  freedom,  the  lateral  branches  are  not  formed  ;  but  the  main  shoot  appears 
arrow-headed,  with  jagged  sides,  as  in  the  figure  C ;  the  sides  or  teeth  being  the 
rudiments  of  the  lateral  spurs.  In  the  field  of  view  other  forms  are  seen  like 
those  in  the  group  D,  most  of  which  resemble  the  variety  C  in  their  incipient 
formation.  Another  kind  with  regular  faces  is  seen  at  A ;  the  breadth  of  this 
crystal  at  the  end  A,  as  measured  by  the  micrometer,  was  found  to  be  one-two- 
hundred  and  seventy -seventh  part  of  an  inch. 

In  India,  saltpetre  forms  upon  the  surface  of  the  ground  in  silky  tufts  and 
slender  prismatic  crystals  ;  especially  when  the  abundant  rains  of  this  tropical 
region  are  succeeded  by  hot  weather.  These  delicate  filaments  aro  swept  from 
the  surface  of  the  soil  into  large  heaps,  which  are  then  leached  like  ashes,  and 
the  liquid  thus  obtained,  after  being  suffered  to  settle,  is  evaporated,  when  the 
nitre  remains  in  a  crystallized  form. 

In  certains  regions  of  India  the  lower  part  of  the  mud-walls  of  the  houses 
becomes  wet  and  black  each  morning  during  the  dry  season,  from  February  to 
May  ;  and  portions  of  the  mud  crumble  down  into  a  fine  powder.  This  dust  is 
swept  up  every  day,  and  contains  about  one-fifth  of  its  weight  of  saltpetre.  It 
is  stated  by  the  natives  that  the  supply  is  abundant  during  those  years  when  the 


102  VIEWS    OF    THE    MICROSCOPIC    WORLD. 

preceding  monsoon-storms  have  been  most  heavy,  and  the  thunder  and  lightning 
that  attend  them  unusually  frequent.  The  earth  from  which  the  nitre  has  been 
extracted,  in  a  year  or  two  becomes  impregnated  again,  and  the  tendency  of  the 
soil  to  reproduce  it  causes  much  trouble  and  annoyance  to  the  occupants  of 
houses.  Bishop  Heber  remarks  "that  the  nitre  can  scarcely  be  prevented  from 
encroaching,  in  a  few  years,  on  the  walls  and  floors  of  all  lower  rooms,  so  as  to 
render  them  unwholesome,  and  eventually  uninhabitable."  To  such  an  extent 
does  it  prevail  at  Tirhoot,  that  it  may  be  brushed  from  off  the  lime  walls  of  the 
houses,  and  other  humid  places,  almost  in  basketful*,  every  two  or  three  days. 

FLOWERS  OF  BENZOIN. — A  species  of  gum,  known  by  the  name  of  Benzoin, 
is  extracted  from  a  tree  which  grows  in  Java,  and  some  other  parts  of  the  East. 
An  incision  is  made  into  its  trunk  and  branches,  and  a  fluid  exudes  from  them, 
which  hardens  upon  exposure  to  the  air,  concreting  into  brittle  masses.  It 
melts  when  subjected  to  a  moderate  heat,  and  sends  forth  a  thick,  white  smoke, 
which  condenses,  upon  the  underside  of  the  cover  of  the  vessel  containing  the 
melted  gum,  in  slender  and  delicate  crystals  of  benzoic  acid.  These  are  beauti- 
fully white  and  transparent,  and  emit  a  fragrant  odor.  A  drop  of  the  solution 
of  this  acid  exhibits  very  elegant  crystallizations  under  the  microscope.  Sharp 
crystals  are  first  perceived  forming  at  the  edges,  transparent,  and  without  color, 
which  soon  push  forward  towards  the  centre  of  the  drop,  in  the  form  of  running 
vines  and  beautiful  tufts  of  mimic  foliage.  Several  specimens  are  delineated  in 
drawing  152,  possessing  the  same  characteristic  form,  but  still  differing  in  some 
particulars.  All  consist  of  similar  minute  crystals  gracefully  clustered  together  ; 
but  while  one  shoots  along  in  light  and  airy  tracery,  as  in  the  right  hand  figure, 
another,  like  that  upon  the  left,  extends  laterally,  and  spreads  its  glittering 
branches  from  side  to  side ;  and  in  different  parts  of  the  field  of  view  other 
configurations  start  forth,  and  rich  tuft-like  figures  are  seen  like  the  central 
forms  of  the  group.  The  largest  tufts  and  vines  appear  dark  to  the  eye  from 
the  immense  number  of  minute  crystals  which  are  there  clustered  together  ;  but 
amid  these,  under  a  subdued  light,  wreaths  of  exquisitely  delicate  foliage  are 
seen,  formed  of  the  purest  crystals,  and  gleaming  like  silver  sprays.  Inter- 
spersed with  the  rest,  crystallizations  in  the  form  of  crosses  occur,  as  shown  in 
the  drawing.  When  the  acid  is  dissolved  in  alcohol,  and  the  solution  spread  upon 
the  glass,  the  crystallization  proceeds  with  great  swiftness,  on  account  of  the 
rapid  evaporation  of  the  spirit.  At  one  moment  the  eye  of  the  observer  gazes 
upon  nothing  but  a  film  of  liquid,  and  at  the  next,  on  a  sudden,  at  a  single 
flash,  order  springs  forth,  and  the  chaotic  surface  is  profusely  studded  with  all  the 
exquisite  and  graceful  combinations  which  have  been  detailed.  The  delineations 
in  the  figure  are  drawn  from  actual  crystallizations,  like  all  the  rest,  and  repre- 
sent forms  of  average  dimensions.  Some  idea  may  be  gained  of  the  smallness 
of  the  crystals,  from  the  fact,  that  the  breadth  of  the  group  a,  6,  is  only  the 
one-six-hundred  and  twentieth  part  of  an  inch. 


N91B3 


1   ' 


ll 


CRYSTALLIZATIONS.  103 

SULPHATE  OF  IRON,  OR  COPPERAS. — This  substance  crystallizes  in  transparent, 
rhomboidal  prisms,  and  appears  of  a  sea-green  color  when  the  crystals  possess 
a  considerable  size.  Under  the  microscope  it  displays  very  regular  and  interest- 
ing combinations.  A  drop  of  an  aqueous  solution  of  the  sulphate  of  iron  must 
be  only  moderately  heated,  when  the  film  of  liquid  is  soon  perceived,  crystal- 
lizing at  the  edges  where  it  is  thinnest ;  the  principal  crystals  pushing  forward 
in  a  straight  direction,  while  at  the  same  time  branches  proceed  from  them  on  either 
side.  These  lateral  shoots  all  start  from  the  main  crystal  at  the  same  inclina- 
tion, and  advance  parallel  to  each  other  with  the  greatest  precision  and  order, 
throwing  out  likewise  secondary  branches,  which  meet  and  combine ;  and  the 
whole  array  of  interlocked  crystals,  its  line  bristling  with  arrow-headed  forms,  is 
Been  steadily  advancing  over  the  field  of  view.  Some  of  these  configurations 
are  massive  in  their  structure,  and  others  more  light  and  delicate ;  but  all  more 
or  less  reveal  the  form  of  the  primitive  crystal ;  and  minute  as  they  are,  their 
solidity  is  apparent  from  the  mingled  lights  and  shadows  that  fall  upon  the  crys- 
tallized surface.  And  very  beautifully  are  these  lights  and  shadows  varied,  as 
the  mirror  is  differently  adjusted,  and  the  illumination  now  plays  brightly  upon 
some  rich  and  glittering  cluster,  and  again  falls  chastened  and  subdued  upon 
the  mimic  gems.  Drawing  153  represents  a  group  of  crystals  of  sulphate  of  iron, 
which,  although  faithful  delineations  of  actual  forms,  cannot  adequately  convey 
an  idea  of  the  rare  beauty  of  the  entire  crystallized  surface.  In  figures  C  and 
D,  the  regularity  of  the  lateral  spurs,  branching  out  from  the  main  stem,  is  very 
marked  and  perfect ;  and  in  E,  a  broad  sheet  of  lateral  crystals  proceeds  from 
the  principal  trunk  parallel  to  each  other.  At  F,  three  long  crystals  are  seen 
side  by  side,  with  bluntly-pointed  heads ;  and  when  under  the  microscope,  the 
crystallization  proceeds  slowly,  its  serrated  line  is  formed  of  heads  like  these, 
which  continually  advancing  into  the  liquid  film,  constantly  maintain  the  same 
shape.  At  H,  a  large,  heavy  crystal,  of  similar  form,  is  seen,  the  length  of  one 
of  whose  re-entering  side,  «,  6,  is  the  three  hundred  and  twelfth  part  of  an 
inch.  The  last  figure,  G,  is  a  specimen  of  a  variety  frequently  beheld  amid  the 
crowded  mass  of  crystallizations.  Minute  crystals,  possessing  the  primitive 
rhomboidal  figure,  are  sometimes  found  at  the  edges  of  the  crystallized  film, 
often  clustered  together  in  grotesque  combinations,  resembling,  with  their  sa- 
lient points  and  re-entering  angles,  the  frowning  bastions  of  a  fortress. 

CAMPHOR. — When  camphor  is  dissolved  in  alcohol,  very  elegant  crystals  are 
formed  upon  a  slip  of  glass,  by  spreading,  in  the  usual  manner,  a  drop  of  the 
solution  over  the  surface. 

The  film  of  the  fluid  crystallizes  with  great  rapidity,  owing  to  the  rapid 
evaporation  of  the  alcohol.  When  the  glass  is  just  prepared  and  placed  under 
the  solar  microscope,  the  image  of  the  drop  is  beheld  upon  the  screen,  as  a  uni- 
formly misty  surface ;  suddenly  it  is  broken  up  in  the  thinnest  part,  which  in  a 
moment  is  studded  with  beautiful  star-like  figures.  Instantaneous  flashes  now 
flit  successively  over  the  remaining  portions  of  the  cloudy  field,  and  simultaneous 


104  VIEWS    OF   THE    MICROSCOPIC    WORLD. 

with  this  motion,  the  same  elegant  radiated  figures  start  forth,  perfect  in  form, 
on  the  ground  over  which  passes  the  creative  wave.  These  configurations  are 
extremely  beautiful,  and  consist  of  delicate  crystals,  which  radiate  from  a  centre, 
most  commonly  in  six  branches,  jvhich  are  nearly  of  the  same  length.  They 
are  formed  like  fern-leaves,  wide  at  the  base,  and  gradually  tapering  to  a  point, 
the  fringes  at  the  sides  being  composed  of  slender,  'feathery  crystals.  Beautiful 
configurations  of  this  kind  are  exhibited  in  the  plate  at  C,  D,  E,  F,  and  G.  A 
and  B  are  branches  of  fern-like  crystals  of  a  different  type,  and  at  H  a  crystal 
is  seen  having  the  form  of  a  cross.  Scarcely  any  heat  is  necessary  to  produce 
these  configurations,  for  the  spirit  quickly  evaporates,  and  the  crystals  that 
originate  are  of  short  duration,  in  consequence  of  the  camphor  itself  being  vol- 
atile. The  crystals  of  camphor  are  very  minute,  for  the  entire  length  of  the 
branch  a,  5,  is  only  the  one  hundred  and  twenty-fifth  part  of  an  inch. 

SAL  AMMONIAC,  OR  MURIATE  OF  AMMONIA. — The  crystals  of  this  salt  are 
among  the  most  elegant  of  those  which  the  microscope  reveals,  and  the  prepared 
solution  crystallizes  with  great  facility.  The  change  commences  at  the  edges  of  the 
film,  and  at  those  places  on  the  surface  where  the  liquid  is  thinnest ;  and 
from  these  points  sharp,  broad,  dagger-shaped  crystals  push  out  in  all  directions. 
The  crystal  appears  at  first  as  a  single  stem  of  the  most  perfect  transparency, 
but  as  it  advances  it  throws  out  at  each  side  blunt  crystals  of  different  lengths, 
parallel  to  each  other,  and,  usually  at  right  angles  to  the  main  shoot.  These 
lateral  spurs  increase  in  length  until  the  middle  of  the  principal  crystal,  when 
they  gradually  diminish  in  extent  until  they  vanish  at  its  remote  extremity. 
The  lateral  branches  often  extend  from  the  principal  crystal  to  a  considerable  dis- 
tance, and  are  themselves  studded  with  minute  crystals  at  the  side,  which  also 
shoot  out  at  right  angles  ;  and  from  these  again  similar  systems  proceed  to  an 
indefinite  extent.  This  mode  of  crystallization  is  shown  in  three  figures  deline- 
ated in  drawing  155.  Here  is  likewise  displayed  in  three  others  another  combina- 
tion, consisting  of  six  broad  and  beautiful  leaves  diverging  from  a  common  cen- 
tre. In  one  of  the  specimens  the  leaves  are  without  branches  ;  but  in  the  others 
they  break  forth  into  crystals  on  either  side  ;  and  each  of  the  six  stems  becomes 
a  silvery  spray.  A  very  common  form,  which  is  likewise  here  exhibited,  is  a 
transparent,  dagger-shaped  crystal,  with  the  blade,  handle,  and  guard,  all  com- 
plete. Beautiful  as  these  delineations  are,  they  can  but  faintly  represent  the 
exquisite  delicacy  of  the  originals,  with  their  distinct  outlines,  symmetrical  combi- 
nation, and  perfect  transparency.  The  crystals  are  quite  small,  the  breadth  of 
the  main  stem  at  a,  in  one  of  the  figures,  being  only  one-jive-hundredth  part 
of  an  inch  ;  and  yet,  small  as  they  are,  these  minute  forms  exhibit  with  dis- 
tinctness, when  the  light  falls  upon  them  in  a  proper  direction,  the  full,  rich,  and 
vivid  play  of  the  prismatic  colors. 

MURIATE  OF  BARYTES.— When  the  muriate  of  barytes  is  dissolved  in  water, 
it  forms  a  clear  and  colorless  solution,  which  speedily  crystallizes  on  the  glass 


r? 


N9155 


I 


N?1S6. 


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£' 


CRYSTALLIZATIONS.  105 

slide  by  the  application  of  a  very  moderate  heat.  The  resulting  configurations 
are  of  exceeding  beauty,  and  no  verbal  description,  or  delineation  of  the  artist, 
can  convey  to  the  mind  a  full  conception  of  the  richness  and  elegance  of  the 
forms  that  are  presented  the  eye  by  the  magic  power  of  the  microscope.  Not 
only  is  the  beholder  charmed  with  the  wonderful  delicacy  and  exquisite  grace 
of  the  figures ;  but  such  is  the  swiftness  with  which  the  fluid  crystallizes,  that  he 
sees  them  in  the  very  process  of  formation,  darting  forth  their  glittering  filaments 
in  all  directions  with  a  velocity  truly  astonishing.  A  quick  formation  belongs 
to  nearly  all  the  crystallizations  herein  described  ;  but  the  very  rapid  change  of  the 
muriate  of  barytes  from  the  liquid  to  the  fluid  state  peculiarly  impresses  this 
circumstance  upon  the  mind.  One  combination  common  to  this  salt,  and  which 
is  delineated  at  A  in  drawing  156,  is  found  near  the  edge  of  the  crystallized  field. 
It  appears  like  a  collection  of  shrubs,  shorn  of  their  leaves,  growing  up  from  the 
midst  of  a  tuft  of  rank  herbage.  The  main  crystals  take  no  particular  direction 
in  reference  to  each  other,  and  the  lateral  branches  appear  likewise  to  be  guided 
in  their  course  by  no  especial  law.  From  crystals  like  these  numerous  branches 
proceed,  dividing  and  sub-dividing  until  an  infinity  of  boughs  and  sprays  are 
seen,  rising  from  a  single  stem,  and  groups  and  groves  of  crystal  trees  spread 
their  fairy  foliage  over  the  whole  field  of  view. 

Another  beautiful  configuration  is  delineated  at  B,  where  the  crystalline  stems 
radiate  from  a  common  centre,  and  diverging  more  and  more  as  they  recede 
from  this  point,  push  forth  on  either  side  buds  and  shoots  of  sparkling  crystals, 
covering  the  entire  circle  throughout  which  they  extend  with  clustering  gems. 

A  third  variety  is  exhibited  at  C.  The  main  crystals  are  here  short  and  thick, 
their  ramifications  occupying  only  a  little  space.  The  secondary  crystals  are 
parallel  to  each  other  and  perpendicular  to  the  parent  stem ;  and  from  these  a 
third  system  proceeds,  governed  by  similar  laws. 

One  part  of  this  last  assemblage  of  crystals  is  singularly  connected  with  the  rest ; 
for  on  the  same  side,  from  a  single  point  in  the  principal  crystal  two  shoots 
emanate  obliquely  from  it  and  at  right  angles  to  each  other  ;  but  the  lateral  spurs 
from  these,  observe  the  same  laws,  in  regard  to  direction,  as  those  in  other  parts 
of  this  combined  figure.  The  size  of  the  crystalline  stems  is  exceedingly  small, 
the  breadth  at  a,  b,  in  this  specimen,  being  only  one-seventeen  hundred  and  six- 
tieth part  of  an  inch. 

The  crystallizations  of  the  muriate  of  barytes,  like  many  others,  exhibit  an  ex- 
tremely beautiful  appearance  when  viewed,  not  by  the  diffuse  light  of  day, 
but  by  a  single  light,  as  a  lamp.  Each  crystal  then  acts  as  a  prism  in  decompos- 
ing the  rays,  and  the  entire  field  of  view  becomes  illuminated  with  the  splendor 
of  the  sevenfold  tints  of  the  rainbow. 

BICHROMATE  OF  POTASSA. — This  salt  produces  very  elegant  combinations, 
the  original  form  of  the  crystals  being  that  of  a  four-sided  prism.  The  solution 
is  of  a  transparent  cherry  color,  and  the  minute  crystals  seen  by  the  microscope 
gleam  with  a  rich  amber  light.  Like  those  of  the  muriate  of  ammonia  they  form 


106  VIEWS    OF    THE    MICROSCOPIC    WORLD. 

with  great  rapidity,  and  the  swift  advance  of  their  spreading  configurations  gives 
full  employment  to  the  eye  of  the  observer.  A  group  of  the  various  combinations 
afforded  by  the  bichromate  of  potassa  is  delineated  in  drawing  157.  A  represents 
the  primitive  crystals  as  they  are  seen  at  the  edges  of  the  film,  but  the  two  most 
common  forms  are  running  vines  and  plume-like  tufts,  consisting  of  numerous 
crystallized  branches  of  the  most  delicate  structure.  The  first  is  often  seen  origi- 
nating in  a  single  stem,  which  as  it  grows,  soon  breaks  up  into  a  thousand  curved 
shoots,  that  interlace  and  entwine  with  each  other,  composing  a  kind  of  irregu- 
lar crystallized  network  extending  over  the  surface  before  occupied  by  the  liquid. 
Two  sprigs  of  this  enwreathed  crystallization  are  delineated  at  B  and  C.  The  lat- 
eral spurs  are  short,  forked,  and  disposed  along  the  stem  without  any  particular 
regard  to  symmetry ;  and  are  often  loaded  with  comparatively  heavy  crystals, 
the  whole  presenting  an  appearance  not  unlike  a  spray  of  withered  herbage 
fringed  with  crystals  of  hoar-frost.  A  specimen  of  the  second  kind  is  shown  at 
D,  where  numerous  slender  ramifications  are  seen  radiating  from  a  single  stem, 
each  filament  being  studded  at  the  side  with  minute  crystals.  These  glitter- 
ing plumes  are  scattered  in  profusion  over  the  whole  field  of  view,  amid  the 
sparkling  network  of  crystallized  vines,  and  the  union  of  these  rich  and  radiant 
configurations  dazzles  the  eye  with  visions  of  rare  and  surpassing  beauty.  A 
singular  form  is  presented  at  E ;  the  solution  has  crystallized  in  circles  around  a 
particle  of  sediment ;  the  circles  are  gemmed  with  crystals  at  the  sides,  and 
terminate  in  branching  sprigs  as  graceful  as  the  leaflets  of  a  flower.  These 
delicate  sprays  are  very  small,  the  breadth  of  the  crystal  at  a  in  F  measuring 
only  one-sixteen  hundred  and  sixtieth  part  of  an  inch. 

SULPHATE  OF  SODA,  OR  GLAUBER  SALTS. — This  salt  crystallizes  slowly  by  the 
application  of  a  gentle  heat,  and  exhibits  a  great  diversity  of  combinations, 
which  are,  for  the  most  part,  massive,  and  stand  boldly  out  upon  the  surface  of 
the  glass.  One  variety  commences  in  a  spicular  cluster,  similar  to  that  delineated 
at  A  in  drawing  158,  the  branches  of  which  spread  out  in  long  needle-shaped 
crystals  on  every  side,  which,  intersecting  with  others  of  similar  nature,  frequently 
form  an  irregular  crystallized  lattice  work.  Sometimes  long  and  massive  crystals 
radiate  from  a  common  centre  like  the  spokes  of  a  wheel.  Another  variety  of 
crystal,  of  a  delicate  white  color,  broad,  pointed,  and  shaped  like  a  feather,  is 
often  seen  advancing  in  the  field  of  view,  and  sending  forth  its  glittering  filaments 
on  either  hand.  In  other  parts  of  the  crystallized  film,  a  number  of  these  crys- 
tals are  beheld  ranked  side  by  side,  like  the  teeth  of  a  comb,  and  the  surface  ot 
each  is  itself  studded  with  still  smaller  crystals.  Rich,  starry  crystals  are  also 
found,  like  those  displayed  in  group  B,  and  the  other  forms  which  are  here  de- 
lineated are  scattered  in  profusion  amongst  the  rest.  Very  beautiful  figures  are 
frequently  observed  near  the  edges  of  the  drop  where  the  salt  is  most  abundant. 
Two  of  these  are  exhibited  at  C  and  D,  the  first  of  which  is  a  heavy  transparent 
configuration  of  considerable  thickness  with  serrated  sides,  formed  of  single  dia- 
mond-shaped crystals.  The  second  is  a  very  singular  crystalline  structure,  and 


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CRYSTALLIZATIONS.  107 

resembles  some  massive  piece  of  sculpture  wrought  with  elaborate  skill.  The 
crystals  that  compose  the  arch-like  figure  are  very  large  in  comparison  with  the 
rest  in  this  cluster,  and  yet  the  distance  from  a  to  6  measures  only  one- three-hun- 
dred and  fifty -seventh  part  of  an  inch. 

VERDIGRIS. — The  crystals  of  verdigris  are  of  a  fine  greenish  blue  color,  and 
have  for  their  primitive  form  that  of  a  lozenge  or  rhomboid.  When  a  drop  of 
the  prepared  solution  is  placed  upon  a  slip  of  glass,  it  begins  to  crystallize  at 
the  edges,  under  the  action  of  a  mild  heat,  and  clusters  of  transparent  crystals,  of 
the  form  exhibited  at  a,  in  drawing  159,  are  seen  gleaming  with  a  rich  blue  tint, 
upon  the  edge  of  the  drop.  Another  form  like  that  at  b  is  likewise  be- 
held  branching  from  a  single  stem,  like  the  leaves  of  the  fleur-de-lis.  A 
similar  spicular  cluster,  in  which  the  stems  are  more  numerous  and  slender,  is 
observed  at  c.  Another  configuration  is  delineated  at  d,  which  originates  in  a 
single,  diamond-shaped  crystal,  one  point  of  which,  possessing  greater  energy 
than  the  others,  has  pushed  forth  a  long  serrated  crystal,  from  which  arrow- 
headed  lateral  forms  proceed,  in  a  direction  parallel  to  each  other. 

The  solution  of  verdigris  does  not  crystallize  with  rapidity,  and  as  the 
liquid  evaporates  slowly  in  the  central  portions  of  the  drop,  delicate  needle- 
shaped  crystals  are  detected  amid  the  larger  forms,  crossing  each  other  in  all 
directions.  A  specimen  of  this  configuration  is  drawn  at  e,  and  throughout  the 
entire  surface  of  the  crystallized  film,  minute  crystals  of  the  first  form  are  pro- 
fusely scattered.  The  larger  crystals  of  verdigris  are  extremely  well  defined, 
and  as  perfect  as  if  cut  by  the  lapidary.  In  the  figure  d  the  breadth  of  one  of 
the  lateral  crystals  at  the  head  ef,  is  one-five-hundredth  of  an  inch. 

SULPHATE  OF  MAGNESIA,  OR  EPSOM  SALTS. — The  crystals  of  this  salt  com- 
bine in  figures  of  exceeding  beauty,  and  with  a  slow  and  steady  motion.  The 
observer  is  thus  enabled  to  examine  at  full  leisure  the  shapeless  fluid,  as  it  grad- 
ually changes  into  the  richest  configurations,  which  grow  and  expand  on  every 
side,  lavishly  adorned  with  the  most  exquisite  and  singular  figures.  The  crys- 
tals are  best  viewed  in  the  evening,  by  the  light  of  a  lamp ;  at  the  moment 
they  begin  to  form,  they  are  then  seen  shooting  along  parallel  to  each  other,  in 
the  shape  of  massive  broad  shafts,  arrow-headed,  and  serrated  on  either  side, 
such  as  are  displayed  at  A  in  drawing  160.  At  times  their  structure  is  more  elabo- 
rate, and  they  somewhat  resemble  long  leaves,  with  strongly  marked  veins  branch- 
ing from  the  main  stem  ;  this  variety  is  delineated  at  B.  As  the  crystals  advance, 
the  lateral  points  or  teeth  likewise  expand  in  broad  crystals,  running,  some  ob- 
liquely and  some  at  right  angles  to  the  principal  figure.  The  lateral  crystals 
likewise  throw  out  from  their  sides  a  third  set,  and  thus  the  ramifications  ex- 
tend until,  weaving  and  interlocking  with  each  other,  the  entire  field  of  view  is 
covered  with  the  crystalline  structure.  This  in  many  parts  resembles,  in  the 
promiscuous  grouping  of  its  figures,  a  surface  composed  of  fern  leaves  placed 
upon  each  other,  without  any  regard  to  regularity ;  but  in  others  the  figures  are 


108  VIEWS    OF    THE    MICROSCOPIC    WORLD. 

seen  interlacing  in  the  most  fantastic  shapes.  A  remarkable  characteristic  of 
these  crystals  is  their  softness  of  tint;  they  shine  with  a  pearly  whiteness,  and 
the  light  comes  through  them  mild  and  subdued,  like  the  gentle  radiance  of  the 
moon,  imparting  such  a  softness  to  these  beautiful  figures  that  they  appear  as 
delicate  as  flower-wreaths,  wrought  on  a  satin  ground.  Another  form  is  exhibited 
in  the  figures  at  C  and  D ;  it  is  a  pearl-colored,  lozenge-shaped  crystal,  and  is 
often  seen  small  at  first,  but  of  perfect  proportions.  As  the  eye  remains  fixed 
upon  it,  it  is  seen  gradually  to  increase  in  size,  retaining  nevertheless,  at  the 
same  time,  its  original  symmetry,  a  result  which  is  effected  by  the  sides  expand- 
ing uniformly  from  the  centre  of  the  crystal.  Several  modifications  of  this  type 
are  presented  in  the  drawing.  A  fourth  variety  consists  of  clusters  of  spicular 
crystals,  such  as  are  depicted  at  F  G,  and  another  configuration  is  exhibited  at 
F,  where  the  massive  crystals  cross  each  other,  and  interlock  like  the  roots  of 
trees.  At  E  the  crystals  form  a  serrated  surface,  resembling  the  plaits  of  a 
frill. 

SULPHATE  OF  COPPER. — The  sulphate  of  copper  affords  a  fine  blue  solution, 
which  forms  quickly,  upon  the  application  of  a  moderate  heat,  into  long  spicular 
crystals,  uniting  and  blending  with  each  other.  The  network  of  the  crystals  is 
clearly  discerned  by  the  unaided  eye,  but  the  microscope  is  needed  to  display 
their  more  intimate  combinations,  and  the  different  configurations  they  assume. 
In  drawing  161  are  delineated  a  number  of  crystals  of  sulphate  of  copper; 
the  long  spicular  figure  C,  at  the  top,  is  that  which  is  first  detected  under  the 
microscope,  pushing  forward  its  sharp  point  into  the  crystallizing  fluid.  As  it 
advances  it  spreads  out  laterally,  sending  forth  numerous  crystals,  mostly  from 
one  side,  which  often  unite  so  compactly  together,  as  to  constitute  a  triangular 
plate.  The  form  it  then  assumes  is  the  same  as  that  which  is  exhibited  at  D. 
A  more  delicate  and  perfect  configuration  is  displayed  at  a  b  ;  the  crystals  of 
which  are  exquisitely  fine,  especially  those  at  the  sides.  Instead  of  being 
blended  together,  as  at  D,  they  are  distinct  and  separate  from  each  other  ;  and  in 
every  set  branch  from  the  main  stem  in  exactly  parallel  directions.  The  dis- 
tance between  the  two  adjacent  principal  crystals  a  and  6,  is  only  the  one  hun- 
dred and  ninetieth  part  of  an  inch.  The  cluster  E  consists  of  short  prismatic 
crystals,  which  are  usually  found  in  groups,  near  the  edges  of  the  liquid,  wherever 
the  film  is  comparatively  thick,  and  the  matter  held  in  solution  quite  abundant. 
Profusely  scattered  throughout  this  locality,  fine  diamond-shaped  crystals  are 
likewise  often  found.  A  rare  configuration  is  delineated  at  F,  consisting  of  a 
minute  and  distinct  portion  of  the  liquid  which  has  concreted  without  regularly 
crystallizing  throughout,  a  circumstance  which  often  happens  when  too  much 
heat  is  applied  to  the  glass  slide.  In  the  midst  of  this  mass  a  beautiful  spiral 
system  of  exquisitely  formed  crystals  is  beheld,  emanating  from  a  central  point, 
and  spreading  its  slender  and  plumy  branches  over  the  entire  transparent 
surface. 


N9161 


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CRYSTALLIZATIONS.  109 

ALUM. — In  drawing  162  are  delineated  several  groups  of  the  crystals  of  alum. 
This  substance  is  for  the  most  part  artificially  produced,  and  is  seldom  found  in 
a  native  state,  though  it  occasionally  appears  as  an  efflorescence,  and  exists  in 
certain  mineral  waters  in  the  East  Indies.  The  primitive  form  of  the  crystals 
of  alum  is  an  octahedron  ;  that  is,  a  regular  solid  contained  within  eight  equal 
faces.  The  combinations  of  the  single  crystals  are  extremely  rich,  and  the  fig- 
ures in  the  drawing  but  faintly  represent  the  exquisite  crystalline  tissue  which  is 
seen  beneath  the  microscope  emerging  from  the  shapeless  fluid  ;  every  part  sym- 
metrically wrought  with  lines  of  fairy  gems,  replete  with  elegance  and  beauty. 
The  crystals  form  rapidly,  and  are  beheld  on  the  slide  shooting  forth  into  the 
liquid  film,  in  figures  like  those  delineated  at  A,  being  arrow-headed  and  serra- 
ted at  the  edges.  Advancing  side  by  side  in  parallel  lines,  they  each  spread 
rapidly  on  either  hand,  throwing  out  lateral  spurs  at  right  angles  to  the  main 
crystals.  From  the  edges  of  these  secondary  crystals,  others  in  like  manner  dart 
forth,  all  weaving  and  interlacing  with  each  other,  and  forming,  with  other  simi- 
lar systems,  one  unbroken,  glittering  sheet.  The  advancing  line  of  such  a  crys- 
talline field,  is  displayed  in  figures  B,  C,  and  D.  Sometimes  the  main  crystals, 
as  at  C,  slightly  diverge  from  each  other.  An  unusual  configuration  is  de- 
lineated at  E,  where  two  sets  of  crystals,  bending  in  parallel  curves,  intersect 
each  other,  and  form,  by  their  union,  a  light  and  graceful  gothic  arch.  The 
breadth  of  the  larger  crystals  across  their  arrow-heads,  /,  k,  measures  about  one- 
two  hundredth  of  an  inch. 

SALT,  OR  CHLORIDE  OF  SODIUM. — In  drawing  163,  an  assemblage  of  crystals  of 
common  salt  is  delineated.  The  primitive  form  of  this  well-known  substance  is 
a  cube,  and  the  crystalline  structure  of  the  fragments  and  masses  in  which  it  is 
found,  is  seen  at  a  casual  glance  with  the  unaided  eye.  A  solution  of  salt,  as  it 
crystallizes,  is  never  seen  spreading  out  into  beautiful  ramifications  ;  but  as  fast 
as  the  fluid  evaporates,  the  surface  of  the  glass  becomes  studded  all  over  with 
minute  and  sparkling  gems  of  salt.  Eight-sided  and  twelve-sided  figures  are 
likewise  formed  by  the  union  of  the  primitive  cubical  crystals.  Another  variety 
which  is  quite  common,  is  that  of  a  hollow  rectangular  pyramid.  It  begins  its 
formation  at  the  surface  of  the  fluid  with  a  small  cube,  upon  the  upper  edges  of 
which  four  rows  of  small  cubes  soon  crystallize.  To  their  upper  and  outer 
edges  other  cubical  crystals  now  attach  themselves,  and  by  degrees  a  hollow  py- 
ramidal structure  is  completed — capped  at  the  smaller  extremity  with  the  origi- 
nal cube.  In  the  drawing  several  cubical  crystals  are  delineated,  together  with 
many  specimens  of  the  hollow  pyramid.  The  length  of  one  of  the  sides  of  the 
crystal  A,  is  the  two  hundred  and  twenty-seventh  part  of  an  inch. 

SNOW. — The  snow-flake,  which  varies  from  more  than  an  inch  to  seven-hun- 
dredths  of  an  inch  in  diameter,  consists  of  an  assemblage  of  exquisitly  minute 
crystals  ;  arid  from  its  beautiful  figures  and  rich  diversity  of  forms,  has  ever  ex- 
cited the  admiration  of  observers. 


no 


VIEWS    OP    THE    MICROSCOPIC    WORLD. 
Fig.  164. 


CRYSTALLIZATIO  NS.  Ill 

When  the  snow  descends  in  a  calm  atmosphere,  the  constituent  crystals  of 
the  flake  are  perfectly  developed,  but  any  agitation  of  the  air,  or  an  increase  in 
moisture  or  temperature,  destroys  their  delicate  structure.  The  single  crystals 
always  unite  at  angles  of  thirty,  sixty,  and  one  hundred  and  twenty  degrees,  but 
by  their  different  modes  of  union,  give  rise  to  several  hundred  distinct  varieties. 
Scoresby,  a  celebrated  Arctic  navigator,  has  enumerated  no  less  than  six  hundred 
kinds,  and  delineated  ninety-six ;  and  Ksemtz,  a  German  meteorologist,  has  ob- 
served twenty  more,  not  figured  by  Scoresby. 

Although  the  varieties  are  so  numerous,  they  are  all  comprised  under 
jive  principal  classes,  which  are  distinguished  as  follows  :  First — crystals  in 
the  form  of  plates,  very  thin,  transparent,  and  of  a  delicate  structure.  This 
class  includes  many  remarkable  varieties,  which  are  represented  by  the  first 
twenty-five  forms  in  cut  164.  Secondly — flakes  either  possessing  a  spherical 
nucleus,  or  a  plane  form  studded  with  needle-shaped  crystals,  like  the  26th 
figure  in  the  cut.  Thirdly — slender,  prismatic  crystals,  usually  six-sided,  but 
sometimes  having  only  three  sides.  Fourthly — pyramids  with  six  sides,  as 
shown  in  figure  27.  Fifthly — prismatic  crystals  having,  perpendicular  to  their 
length,  both  at  the  ends  and  in  the  middle,  thin  six-sided  plates  as  delineated 
in  figures  28,  29,  and  30.  The  last  two  classes  are  extremely  rare,  Scoresby 
having  observed  the  fifth  but  twice,  and  the  fourth  only  once  in  all  his  voyages. 

The  crystallization  of  aqueous  vapor  is  beautifully  displayed  when  a  thin  film 
of  moisture  is  frozen  upon  a  window  pane.  Then,  in  addition  to  single,  star-like 
crystals,  exquisite  branching  configurations  are  seen,  extending  their  glittering 
lines  in  all  directions.  When  water,  in  a  body,  begins  to  freeze,  similar  results 
occur,  and  at  such  times,  along  the  edge  of  a  rivulet,  long,  needle-shaped  crys- 
tals will  be  seen,  darting  from  the  ice  that  fringes  the  bank  towards  the  centre 
of  the  stream,  and  which,  rapidly  interlacing  with  each  other,  soon  unite  into 
one  compact  mass.  Often,  upon  raising  a  thin  sheet  of  ice  from  the  water,  the 
under  surface  will  be  observed  covered  with  a  network  of  crystals.  The  snow, 
on  account  of  its  light  and  branching  crystallization,  descends  softly  upon  the 
earth,  clothing  its  surface  with  a  fleecy  mantle,  which  effectually  shields  the 
tender  plants  from  the  inclemency  of  the  wintry  season.  If  it  had  been  ordered 
otherwise,  and  all  the  moisture,  that  now  forms  the  snow,  had  fallen  in  solid 
masses  of  ice,  like  hail,  the  evils  which  would  have  arisen  under  such  a  pro- 
vision in  the  economy  of  nature,  must  have  been  many  and  great. 

ON  CRYSTALS  FOUND  IN  PLANTS. 

It  has  been  proved,  by  the  microscopic  examinations  of  distinguished  natural- 
ists, that  saline  substances  are  spontaneously  crystallized  within  the  cells  of  plants  ; 
the  crystals  having  been  found  existing  in  infinite  numbers  throughout  the  bark, 
wood,  and  leaves  of  a  great  variety  of  trees  and  shrubs.  The  facts  stated  in 
this  section  are  mostly  taken  from  an  interesting  paper,  read  before  the 
Association  of  American  Geologists,  by  Professor  J.  W.  Bailey,  of  West  Point, 


112 


VIEWS    OF    THE    MICROSCOPIC    WORLD. 


detailing  numerous  discoveries  made  by  himself.  The  attention  of  Prof.  B.  was 
accidentally  led  to  the  pursuit  of  this  subject  by  noticing,  one  day,  the  ashes  of 
a  hickory  ember,  in  which  the  natural  structure  of  the  wood  was  preserved  unin- 
jured, by  the  saline  matter  which  had  resisted  the  action  of  the  fire.  In  order 
to  preserve  this  structure,  the  Professor  prepared  a  slip  of  glass  with  melted  Canada 
balsam,  and  touching  the  ashes  gently  with  the  adhesive  side,  the  delicate  longi- 
tudinal section  was  transferred  to  the  balsam,  and  became  firmly  fixed  in  this 
substance  as  it  cooled  and  indurated ;  -each  part  of  the  structure  retaining  the 
same  relative  position  as  it  possessed  in  the  wood.  When  the  preparation  was 
placed  under  the  microscope,  long  rows  of  polygonal  bodies  of  a  brownish  hue 
were  clearly  perceived.  Similar  bodies  were  discovered  in  the  ashes  of  the  oak, 
and  in  those  of  most  dicotyledonous*  trees,  both  native  and  foreign,  constituting 
a  large  proportion  of  the  insoluble  matter  of  the  ashes. 

Prof.  Bailey  was  at  first  in  doubt,  whether  these  bodies  were  in  fact  true  crys- 
tals, or  simply  saline  matter  which  had  taken  the  form  of  the  cells  in  which  it 
had  concreted. 

This  doubt  was  solved  by  observing  the  bark  of  hickory  when  illumined  by 
the  rays  of  the  sun  ;  numerous  glittering  particles  were  then  seen,  which  proved, 
on  examination,  to  be  crystals  ;  for  when  thin  layers  of  bark,  or  sections  of  wood 
and  bark  were  viewed  by  a  microscope,  the  crystals  were  detected  imbedded  in  their 
natural  position. 

They  were,  however,  better  seen  by  scraping  the  bark  upon  a  plate  of  glass, 
upon  moistening  which  with  the  breath,  the  crystals  were  made  to  adhere  to 
the  surface,  while  the  woody  particles  were  readily  blown  off.  When  placed 
under  the  microscope  the  glittering  atoms  then  appeared  as  beautiful  transparent 
crystals,  having  the  forms  exhibited  in  figures  165,  166,  167,  168,  169  and  170  ; 

some  being  single  as  in 
165,166,  and  others  pos- 
sessing a  com  pound  form, 
as  shown  in  figure  168. 

These  crystals,  when 
prepared  with  balsam, 
were  identical  in  every 
particular  with  the  poly- 
gonal bodies  found  in  the 
ashes. 

These  singular  and  interesting  results  led  Prof.  B.  to  extend  his  investigations, 
and  he  had  the  pleasure  of  discovering  that  the  bark  of  every  species  of  oak, 
birch,  chestnut,  poplar,  elm,  locust,  and  of  all  the  common  fruit  trees,  as  the  apple, 
pear,  plum,  cherry  ;  and  likewise  of  a  great  number  of  others,  were  filled 
with  crystals  crowded  together  in  vast  numbers.  When  thin  layers  of  the 


165. 


*  From  the  Greek  dis,  double,  and  cotyledon,  a  seed-leaf.    Trees  whose  seeds  divide  into  two 
parts,  as  the  sprout 


CRYSTALLIZATIONS. 


113 


bark  were  moistened,  and  examined  by  the  microscope,  the  arrangement  of  crys- 
tals appeared  like  an  elegant  piece  of  mosaic  work,  as  shown  in  figure  171,  which 
is  a  section  of  the  bark  of  a  species  of  poplar,  the  crystals  in 
the  cells  of  the  bark  being  either  single  or  compound.  The  bark 
of  the  locust,  willow,  chestnut  and  various  other  trees  exhibits  a 
similar  appearance.  In  the  densest  woods,  such  as  mahogany  and 
lignum  vita3,  the  crystals  may  be  found  by  scraping  the  wood  into 
a  watch-glass  filled  with  water,  picking  out  the  woody  particles 
and  then  examining  the  residue ;  and  if  by  this  process  the  crystals 
are  in  any  case  sparingly  discovered,  they  will  be  revealed  in  great 
quantities  if  the  ashes  of  the  wood  to  be  examined  are  imbedded 
in  balsam  in  the  manner  before  described. 

The  crystals  are  likewise  detected  in  the  minute  particles  that 
fall  from  worm-eaten  wood,  or  sawdust,  and  in  the  finer  par- 
ticles of  ground  dye-woods,  such  as  fustic  Brazil  wood,  camwood, 
logwood,  sandal  wood,  &c. 

Prof.  B.  next  proceeded  to  examine  the  leaves  of  trees,  which 
were  likewise  found  to  abound  in  crystals.  By  slowly  and  care- 
fully burning  the  leaf  until  the  ashes  became  white,  and  covering  the  residuum 
with  Canada  balsam,  the  incombustible  portions  of  the  leaf  exhibited  a  skeleton 
of  its  figure.  When  a  full  grown  leaf  was  thus  prepared  and  placed  under  the 
microscope,  the  course  of  the  minutest  veins  in  the  leaf  was  seen  traced  out  in 
the  ashes  by  a  row  of  transparent  crystals.  In  young  leaves  these  crystals  were 
observed  only  to  exist  in  the  main  stem,  and  along  some  of  the  principal  branches. 
In  the  leaves  of  other  plants  the  arrangement  of  the  crystals  was  found  to  be 
different,  being  scattered  throughout  the  cellular  tissue  in  star-like  groups.  The 
crystals  of  the  primitive  form,  represented  in  figures  172,  173,  1*74,  175,  176  and 
177,  were  found  by  Prof.  B.  to  exist 
abundantly  in  more  than  one  hundred 
species  of  plants,  belonging  to  more  than 
thirty  different  families,  which  comprise 
the  great  majority  of  dicotyledonous  trees 
and  shrubs,  besides  many  herbaceous 
plants.  The  primitive  form  displayed 
in  figures  165,  166,  167,  168,  169, 
170  and  171,  was  found  to  be  far 
more  sparsely  scattered  in  dicotyledo- 
nous plants,  than  the  forms  found  in  the 
last  set  of  figures ;  while  a  third  form 
which  is  exhibited  in  figures  178  and( 
179,  is  more  abundantly  discovered  than 
the  second  form  in  the  same  division 
of  plants,  and  is  believed  by  Prof.  B. 
to  be  composed  of  crystals  of  the  two 
first  forms.  8 


Fig.172. 


Fig.173. 


175. 


176. 


177. 


114 


VIEWS    OF    THE    MICROSCOPIC    WORLD. 


The  size  of  these  crystals  is  very  small,  not  being  greater  in  some  trees,  as  the 
178  Fig  179  locust,   willow,     &c.,    than     the 

twelve  hundred  and  fiftieth  of  an 
inch  in  length ;  but  their  number 
is  so  great  that  within  the  com- 
pass of  a  square  inch  of  bark, 
not  thicker  than  a  sheet  of  writ- 
ing paper,  more  than  a  million  of 
these  beautiful  gems  are  collected  together.  And  when  we  reflect,  says  Prof.  B., 
"  upon  the  number  of  such  layers  contained  in  the  thickness  of  the  bark,  and 
the  number  of  square  inches  given  by  the  surface  of  a  large  tree,  including  all 
its  branches,  and  then  consider,  that  in  addition  to  all  this,  the  amount  of  crys- 
tals contained  in  the  leaves,  wood  and  roots  is  to  be  taken  into  account,  we  find 
that  the  number  of  crystals  in  a  single  tree  is  enormous  beyond  all  con- 
ception. Yet  the  greater  number  of  trees  in  the  forests,  not  only  in  this  but 
in  all  countries,  are  as  full  of  these  bodies  as  the  specimens  exhibited  in  figure 
171."  When  the  crystals  found  in  wood  are  subjected  to  chemical  tests  they 
are  generally  found  to  be  composed  of  oxalate  of  lime.  Between  the  figures 
178  and  179  a  small  scale  of  measurement  is  seen,  which  is  magnified  to  the 
same  extent  as  the  crystals  above  described.  The  true  length  of  the  scale  in 
the  cut  is  one-Jive  hundredth  of  an  inch,  and  each  division  is  equal  in  extent  to 
one-twenty  Jive  hundredth  of  an  inch  /  by  comparing  these  divisions  of  the  scale 
with  the  size  of  the  crystals,  their  exceeding  minuteness  is  at  once  recognised. 
In  figure  180  is  exhibited  a  collection  of  crystals  obtained  in  the  manner  de- 
scribed by  Prof.  Bailey.  Fix- 
ed in  the  indurated  balsam 
they  appear,  in  vast  numbers, 
under  the  microscope,  of  a 
brown  color,  and  bearing  a  re- 
semblance in  their  shape  to 
kernels  of  rice.  A  single  crys- 
tal measures  in  length  one-six 
hundred  and  twenty-fifth  part 
of  an  inch. 

The  delicate  crystalline  tra- 
cery existing  in  the  burnt  ashes 
of  a  maple  leaf,  is  beautifully 
displayed  in  figure  181.  The 
leaf  from  which  the  drawing 
was  taken  was  prepared  in  the 
way  above  stated,  when  upon 
placing  a  portion  of  the  ashes 
beneath  the  microscope,  fine  lines  of  brilliant  crystals  were  beheld,  as  exhibited  in 
the  figure,  following  all  the  minute  ramifications  of  the  leaf.  Some  of  the  lines 


CRYSTALLIZATIONS. 


115 


Fig.  181. 


were  more  or  less  broken,  on  account  of  the  fragile  nature  of  the  ashy  film  ;  but 
many  were  preserved  entire,  and  •  exhibited  in  the  field  of  view,  the  crystalline 
network  of  the  figure.  With- 
in the  compartments  formed 
by  the  chains  of  crystals,  dark 
masses  are  beheld,  which  are 
crystals  of  a  larger  size.  The 

small     crystals     measure     in 

^  ™  ^^ 

'»*X$ 


length  one-two  thousandth  part 
of  an  inch,  and  the  larger  one- 
seven  hundred  and  seventy- 
fifth  part  of  an  inch. 

Amid  the  starch  globules  of 
potatoes  and  in  the  outer  coat- 
ing of  the  bulb  of  the  onion, 
crystals  have  likewise  been  a 
found,  differing  in  form  from 
all  the  preceding.  In  figure  182 
the  thin  coating  of  an  onion  is 
delineated  as  it  appears  when 
magnified.  This  tissue  is  di- 
vided up  into  cells  in  which 
the  crystals  are  formed.  Their  shapfc 


is  that 


length,  they  measure  one-eight  hundred  and  thirtieth  part  of  an  inch. 


and,  in 


Fig.  182. 


116  VIEWS    OF   THE   MICROSCOPIC    WORLD. 


CHAPTER   VI 

PARTS    OF    INSECTS,    AND    MISCELLANEOUS    OBJECTS. 

Insects  and  mites,  of  mean  degree, 

That  swarm  in  myriads  o'er  the  land, 

Moulded  by  Wisdom's  artful  hand, 

And  curled  and  painted  with  a  various  dye ; 

In  your  innumerable  forms 

Praise  Him  that  wears  th'  ethereal  crown, 

And  bends  His  lofty  counsels  down 

To  despicable  -worms. — WATTS. 

EYES. — Nothing  within  the  whole  range  of  his  investigations  has  more  elicited 
the  admiration  of  the  philosopher,  than  the  wondrous  structure  of  the  human 
eye.  Exceedingly  complex  in  all  its  arrangements,  it  abounds  with  exquisite 
contrivances  for  securing,  under  every  circumstance,  distinct  vision  ;  and  so 
complete  are  the  several  parts  in  themselves,  and  so  admirably  adapted  to  each 
other,  that  it  is  justly  deemed  the  most  perfect  of  all  optical  instruments. 
Upon  its  curved  and  crystal  front,  fall  the  rays  of  light  from  unnumbered  objects, 
spread  over  a  landscape  miles  and  leagues  in  extent ;  and  the  luminous  lines 
converging  in  the  eye  with  unerring  accuracy  to  the  interior  surface,  form  a 
faithful  picture  of  the  entire  scene,  within  the  compass  of  a  finger-nail.  Perhaps 
a  vast  city  is  immediately  before  it,  with  'its  splendid  panorama  of  towers  and 
turrets,  spires  and  cupolas,  piles  of  massive  buildings  and  thronged  streets ; 
while  beyond,  the  harbor  is  crowded  with  the  barks  of  commerce,  and  bays,  and 
misty  isles  stretch  away  in  the  dim  distance ;  yet  all  these  are  perfectly  delin- 
eated upon  the  retina,  in  their  just  proportions  and  natural  colors. 

But  if  our  wonder  is  excited  when  contemplating  the  structure  of  the  eye 
of  man,  and  of  other  animals,  it  is  still  more  heightened  upon  examining  the 
visual  organs  of  insects,  beneath  the  powerful  glasses  of  the  microscope.  The 
eyes  of  insects  differ  from  those  of  other  animated  existences,  chiefly  in  respect 
to  number,  form  and  arrangement.  In  some,  as  in  the  spider,  the  number  varies 
from  six  to  eight,  possessing  such  a  diversity  in  their  mutual  arrangement,  that 
their  relative  positions  have  been  employed  by  writers  to  designate  the  several 
species.  Thus,  in  one  kind  the  eyes  are  arranged  as  in  figure  183  ;  in  another 
as  shown  in  figure  184  ;  and  in  a  third  according  to  figure  185,  and  so  on. 

Fig.  183.  Fig.  184.  Fig.  185. 

>°  /  O    O  oooo 

-O  oooo 


PARTS    OF    INSECTS,    AND    MISCELLANEOUS    OBJECTS.  117 

The  scorpion  has  six  visual  organs,  and  the  centipede  twenty ;  but  other  in- 
sects, as  the  butterfly  and  dragon-fly,  are  gifted  with  a  vast  number  of  eyes,  set 
in  a  common  ball,  to  which  the  name  has  been  given  of  reticulated,  or  network 
eyes.  These  complex  organs  appear  to  be  designed  for  horizontal  and  down- 
ward vision ;  while  coronet  eyes  are  found  placed  upon  the  front  and  top  of  the 
heads  of  insects.  These  latter  organs  appear  as  round,  transparent,  and  shining 
points,  and  are  supposed  to  be  employed  for  upward  vision ;  they  are  usually 
three  in  number,  and  are  generally  arranged  in  the  form  of  a  triangle. 

RETICULATED  EYES. — When  the  eye  of  a  butterfly  or  dragon-fly  is  viewed 
through  a  powerful  microscope,  it  resembles  a  piece  of  network,  and  presents 
the  appearance  of  a  honeycomb ;  each  apparent  cell  being  a  perfect  eye.  The 
outer  surface  of  each  is  bright,  polished,  and  round,  like  that  of  the  human  eye, 
and  reflects  as  a  mirror  the  images  of  surrounding  objects.  What  therefore  is 
commonly  termed  the  eye  of  the  dragon-fly,  silk-worm,  bee,  and  of  other  insects 
having  similar  organs  of  sight,  is  in  fact  a  complex  instrument  of  vision,  con- 
sisting of  a  great  number  of  single  eyes,  arranged  in  a  globular  case,  each  capa- 
ble of  forming  distinct  images  of  the  objects  before  it.  Dr.  Hooke  discovered 
no  less  than  YOOO  single  eyes  in  the  compound  eye  of  a  horse-fly,  while  accord- 
ing to  the  computation  of  Leuwenhoeck,  more  than  12,000  are  contained  in  that 
of  the  dragon-fly ;  and  M.  Puget  counted  in  each  of  the  reticulated  organs  of 
some  butterflies  which  he  examined,  the  astonishing  number  of  17,325  lenses, 
each  constituting  a  perfect  eye.  Optical  artists  have  constructed  an  instrument 
called  a  multiplying  glass,  by  taking  a  solid  piece  of  glass,  bounded  on  one  side 
by  a  plane,  and  on  the  other  by  a  curved  surface,  and  then  grinding  and  polish- 
ing the  latter  into  a  number  of  flat  faces,  still  preserving,  however,  the  general 
curvature.  When  a  single  object,  as  a  flower,  is  beheld  through  this  instrument, 
its  images  are  multiplied  in  proportion  to  the  number  of  exposed  faces,  and  are 
all  symmetrically  arranged  together,  if  the  faces  of  the  glass  have  been  cut  with 
regularity. 

Reticulated  eyes  operate  in  the  same  manner ;  and  naturalists,  by  carefully 
preparing  these  organs,  and  observing  objects  through  them  with  the  aid  of  a 
microscope,  have  been  surprised  and  delighted  at  the  wonders  that  have  met 
their  view.  Not  only  are  objects  multiplied,  but  they  are  also  diminished  to  a 
surprising  degree.  As  Puget  gazed  at  a  soldier  through  the  eye  of  a  flea,  an 
army  of  pigmies  suddenly  appeared  before  him,  and  the  flame  of  a  candle 
flashed  forth  with  the  splendor  of  a  thousand  lamps.  When  Leuwenhoeck,  in 
like  manner,  directed  his  sight  to  the  steeple  of  a  church  two  hundred  and 
ninety-nine  feet  high,  and  distant  seven  hundred  and  fifty  feet  from  the  place 
where  he  stood,  it  appeared  no  larger  than  the  point  of  a  cambric  needle. 

The  reticulated  eyes  of  many  flies  shine  with  the  brilliancy  of  the  finest  gems, 
and  gleam  with  the  richest  hues  of  light.  In  some  the  tints  are  red,  in  others 
green,  while  a  third  class  glow  with  a  play  of  colors  of  surpassing  beauty, 
formed  of  mingled  yellow,  green  and  purple.  Some  ephemeral  insects  are  gifted 


118 


VIEWS    OF    THE    MICROSCOPIC    WORLD. 


Fig.  186. 


Fig.  187. 


with  no  less  than  four  of  these  wonderfully  complex  organs,  the  ordinary  pair 
being  of   a  brown  color,  while  the  additional  pair,  shining  with  a  beautiful 
citron  hue,  rise  side  by  side  from  the  upper  part  of  the 
head.     The  form  of  the  single  lenses  in  reticulated  eyes 
is  not  the  same  in  every  insect  endowed  with  this  curious 
organ  ;  for  in  the  compound  eye  of  the  dragon-fly  and 
honey-bee,  the  lenses  are  six-sided ;  while  in  that  of  the 
lobster  they  possess  a  square  form.      In  figure   186   is 
!  shown  a  portion  of  the  cornea  of  the  compound  eye  of 
a  dragon-fly,  the  single  eyes  of  which  are  seen  to  be  six- 
sided,  and  regular  hexagons.     In  certain  positions,  in  re- 
spect to  the  direction  of  the  light,  they  gleam  with  a  rich 
golden  hue,  and  three  parallel  borders  are  discerned,  which 
divide  the  single  eyes  from  each  other.      The  inner  circle 
in  figure  187  represents  the  same  object  of  its  natural  size.      Figure   188  pre- 
sents a  magnified  view  of  a  part  of  the  complex  eye  of 
a  lobster,  composed  of  a  great  number  of  single  eyes, 
possessing  a  square  form  ;  the  real  size  of  the  object  is 
shown  by  the  smaller  circle  in  figure  189. 

The  eyes  of  the  bee,  which  are  delineated  in  figure 
190,  are  described  by  Swammerdam  as  being  profusely 
covered  with  hairs,  which  pierce  through  the  outer  cov- 
ering of  the  eye,  in  the  same  manner  as  the  hairs  of  the 
human  body  penetrate  through  the  skin.  These  hairs 

©are  very  numerous,  bristling  in  thick  profusion  over  the 
eye,  and  are  supposed  to  perform  the  office  of  eye-lashes 
Flg'  189'  or   eye-brows,  in   protecting  the   organ  from    dust,    or 
any  similar  annoyances  that  might  work  it  harm.     In  this  figure,    the  com- 
pound eyes  of  the  bee,  with  the  parts  adjacent,  are  beautifully  and  distinctly 
revealed. 

The  upper  part  of  the  wood  cut  exhibits  one  of  the  eyes  in  its  perfect  state, 
composed  of  hexagonal  lenses,  and  bristling  with  hair.  In  the  lower  por- 
tion of  the  same  figure,  the  other  complex  eye  is  shown,  deprived  of  some  of 
its  hexagonal  lenses  in  order  that  its  structure  may  be  perceived  :  the  lenses  or 
single  eyes  are  here  seen  to  have  the  shape  of  a  pyramid.  The  three  oval 
figures,  situated  together  in  the  angle  formed  by  the  two  compound  eyes  are 
the  coronet  eyes  of  the  insect,  while  the  two  branching  members  that  curve  over 
the  reticulated  eyes,  are  the  antennae  of  the  bee.  Between  these  the  head  is 
thickly  covered  with  plumes  of  hair.  Figures  191  and  192,  represent  seven  of 
the  hexagonal  lenses,  very  highly  magnified,  and  which,  in  192  are  exhibited 
bristling  with  hair. 


PARTS    OF    INSECTS,    AND    MISCELLANEOUS    OBJECTS. 
Fig.  190. 


119 


120  VIEWS    OF    THE    MICROSCOPIC    WORLD. 


Fig.  191. 


Fig.  192. 

WINGS. — The  wings  of  insects  afford  curious  and  interesting  objects  for  mi- 
croscopical examination ;  since  in  form  and  structure  their  diversity  is  endless, 
and  their  rich  adornments  and  exquisite  hues  are  often  surpassingly  beautiful. 
When  magnified,  a  great  number  of  minute  joints  are  brought  to  view,  by  means 
of  which  the  gauze-like  wings  of  many  of  these  little  creatures  are  at  one  time  cu- 
riously folded  up  within  their  shelly  cases,  and  at  another  are  instantly  expanded 
for  flight ;  while  numerous  branches  of  veins,  nerves  and  muscles  extend  through- 
out these  delicate  structures,  conveying  life,  strength,  and  action  to  every  part. 
The  hard  and  shell-like  cases,  under  which  these  transparent  wings  are  securely 
folded,  are  usually  highly  polished,  and  are  often  adorned  with  elegant 
flutings,  and  a  rich  diversity  of  splendid  tints.  The  diamond-beetle  possesses  all 
these  beauties,  and  is  regarded  as  one  of  the  most  brilliant  objects  in  nature. 
Its  head,  wings,  and  legs  are  studded  with  scales,  glowing  with  the  resplendent 
colors  of  the  sapphire,  ruby,  and  emerald ;  and  it  is  said,  that  in  Brazil,  where 
they  are  found,  such  is  the  dazzling  splendor  of  their  hues,  that  the  eye  cannot 
endure  their  radiance  as  they  fly  in  swarms  through  the  air  upon  a  sunny  day. 
In  figure  193  the  wing  of  an  earwig  is  shown,  of  its  natural  size,  and  the  same 
is  also  there  delineated  as  it  appears  when  magnified.  The  upper  part  of 
the  large  cut  represents  the  wing-case,  which  is  opaque  and  shelly ;  while  the 
rest  of  the  figure  exhibits  the  greater  part  of  the  wing,  which  is  thin  and 
transparent,  and  folds  up  neatly  beneath  the  wing-case,  which  is  not  more  than 
one-sixth  of  the  entire  wing  in  size.  Some  of  the  ribs  are  seen  radiating  to  the 
border,  like  the  sticks  of  a  fan,  from  a  small  space  in  the  upper  part  of  the 
wing,  while  others  intervene  of  shorter  length,  and  proceed  from  the  margin 
half  way  towards  this  central  spot.  All  these  ribs  are  connected  together  by  a 
band  that  runs  along  parallel  to  the  margin  ;  the  entire  arrangement  being  evi- 
dently contrived  so  as  to  impart,  at  once,  strength  and  lightness  to  the  wing,  and 


PARTS    OF    INSECTS,    AND    MISCELLANEOUS    OBJECTS. 


121 


thus  facilitate  its  rapid  motion.  When  the  wing  closes,  the  insect  first  turns  back 
the  marginal  part,  and  then  closes  the  ribs  in  the  manner  of  a  fan,  folding  up, 
within  a  small  compass,  the  entire  delicate  structure  of  the  wing,  under  the  pro- 
tection of  the  strong  shield  of  the  wing-cover. 

Fig.  193. 


The  wing-cases  are  not  in  all  instances  composed  of  a  horny  substance  ;  since 
among  the  beetle  tribe  they  frequently  consist  of  a  softer  material  like  leather. 

When  the  insect  is  preparing  to  fly,  the  wing-cases  are  opened  to  such  an  ex- 
tent as  to  allow  full  play  to  the  wings  ;  the  insect  then  launches  into  the  air, 
striking  it  vertically  with  these  delicate  organs,  while  the  wing-cases  are  kept  im- 
moveable  during  the  whole  time  of  flight.  The  resistance  presented  to  the  atmos- 
phere by  the  latter  is  supposed  to  facilitate  in  some  way  the  motions  of  these  lit- 
tle beings.  The  bodies  of  insects,  like  the  beetle,  are  almost  in  an  upright  posi- 
tion, during  their  flight,  and  present  a  singular  appearance,  in  the  case  of  the 
larger  kinds,  as  they  move  heavily  and  laboriously  along.  The  wings  of  the 
beetle  are  for  the  most  part  of  great  extent,  and  the  ribs  that  ramify  all  over  their 
surface  are  stronger  than  those  which  are  found  in  the  wings  of  other  orders  of 
insects ;  and  are  so  arranged  as  to  strengthen  and  support  every  part.  In  addi- 
tion to  what  has  already  been  remarked  regarding  the  structure  of  the  wings  of 
insects,  it  may  be  further  observed,  that  the  ribs  are  hollow  tubes  originating  in 
the  trunk,  and  that  within  them  are  tubular  vessels,  which  are  supposed  to  be 
air-vessels  communicating  with  the  organs  of  respiration  in  the  trunk. 


122 


VIEWS    OF    THE    MICROSCOPIC    WORLD. 


Fig  194 


HEMEROBIUS  PERL  A.*— In  cut    194   is   delineated    the  wing  of  the  Heme- 

robius  Perla,  both  magnified  and  of  its 
natural  size.  This  insect  receives  its 
appellation  from  the  short  duration  of  its 
life,  which  lasts  but  two  or  three  days. 
Its  wing  is  extremely  elegant  and  deli- 
cate, and  is  formed  of  a  membrane  as 
thin  as  the  finest  gauze  ;  while  slender 
ribs,  fringed  with  hairs  of  a  greenish 
tinge,  are  seen  strengthening  the  wing 
and  running  both  lengthwise  and  oblique- 
ly to  the  margin.  From  these  ribs  late- 
ral branches  proceed,  in  directions  for 
the  most  part,  parallel  to  each  other  ;  and 
from  the  latter  a  third  series  arises ;  the 
whole  forming  a  strong  and  compact  net- 
work bound  firmly  together.  In  addition 
to  the  beauty  and  regular  structure  of  its 
wings,  this  insect  is  otherwise  adorned,  its 
body  being  tinged  with  a  delicate  green, 
while  its  two  eyes  glitter  like  beads  of 
polished  gold.  A  striking  instance  is 
here  afforded  of  the  care  bestowed  by 
our  Heavenly  Father  upon  one  of  the 
smallest  and  least  enduring  of  his  works ; 
for  the  Hemerobius  in  the  course  of  a 
few  hours  comes  into  being,  matures 
and  dies  ;  completing,  in  this  short  space 
of  time,  the  whole  round  of  its  existence, 
and  yet  its  Creator  has  not  only  bestowed 
upon  it  those  organs  and  powers  which 
are  necessary  for  the  discharge  of  the  va- 
rious functions  of  its  life,  but  has  not 
deemed  it  beneath  him  to  lavish  upon  it 
the  bright  gifts  of  beauty. 

FEATHERS  OF  MOTHS  AND  BUTTER- 
FLIES.— A  certain  order  of  insects,  which 
includes  Moths  and  Butterflies,  have  re- 
ceived the  name  of  Lepidopteraf  from 
the  peculiar  construction  of  their  wings. 
These  members  are  covered  with  a  fine 

*  From  the  Greek  hemera,  a  day,  and  bios,  life. 
f  From  the  Greek  lepis,  a  scale,  and  ptera,  wings. 


N9199. 


•;'.M9T. 


•  °196. 


PARTS    OF    INSECTS,    AND    MISCELLANEOUS    OBJECTS.  123 

dust,  resplendent  with  the  most  brilliant  colors,  adorning  their  variegated  surface. 
When  this  dust  is  examined  by  the  microscope,  it  is  discovered  to  consist  of  a 
vast  number  of  minute  feathers  or  scales,  differing  in  form,  and  as  remarkable 
for  the  elegance  and  symmetry  of  their  structure  as  for  the  beauty  of  their  hues. 
Their  shape  not  only  varies  in  different  insects,  but  the  same  insect  possesses 
feathers  of  different  forms.  Some  are  long  and  slender,  others  short  and  broad ; 
these  are  smooth  at  the  edges,  and  those  serrated  or  notched  ;  one  kind  is  tri- 
angular and  a  second  oval.  When  viewed  under  the  microscope,  these  scales  are 
found  to  be  terminated  by  a  short  stem,  that  connects  them  with  the  wing,  and 
their  surfaces  are  grooved  in  lines  and  stripes,  which  take  different  directions  in 
different  scales.  In  some  feathers  two  or  more  sets  of  lines  are  discerned  cross- 
ing each  other.  When  this  feathery  dust  is  brushed  away  from  the  wing  of  a 
butterfly,  the  surface  below  appears  like  the  wing  of  the  Hemerobius — a  network 
of  ribs  connected  by  a  delicate,  transparent,  and  elastic  membrane.  The  ribs  are 
hollow,  by  which  contrivance,  a  wing,  though  broad  and  extended,  still  retains  its 
lightness,  and  on  the  membrane  rows  of  dots  are  perceived,  where  the  stems  of 
the  scales  were  attached  to  its  surface.  On  those  parts  where  the  dust  remains, 
the  little  particles  are  seen  magnified  into  feathers,  symmetrically  arranged  and 
overlapping  each  other  like  the  scales  on  a  fish.  These  several  appearances  are 
beheld  in  drawing  195,  which  represents  a  portion  of  the  wing  of  a  butterfly, 
called  the  Papilio  Archippus,  partially  divested  of  its  scales.  In  this  magnified 
view  the  lighter  parts  of  the  drawing  represent  the  delicate  exposed  membrane 
of  the  wing,  while  in  the  rest  of  the  figure  it  is  covered  with  scales,  which  are 
of  a  rich  brown  hue,  partially  overlapping  each  other  in  regular  rows.  The 
several  lines  of  dark  spots  that  cross  the  membrane  of  the  wing  are  the  places 
where  the  stalks  of  the  feather  were  fastened  to  its  surface.  The  breadth  of 
these  spaces  is  the  sixteen  hundred  and  sixty-sixth  part  of  an  inch,  and  the 
width  of  one  of  the  scales  the  two  hundred  and  fiftieth  part  of  an  inch.  The 
scales  on  the  wings  of  an  insect,  termed  the  Lepisma  Saccharina,  are  of  two 
kinds,  one  set  being  arranged  as  usual  in  rows,  and  the  other,  possessing  a  differ- 
ent shape,  are  inserted  between  and  over  the  former,  fastening  them  firmly  down 
in  their  places.  In  some  instances  the  scales  are  distributed  over  the  membrane 
without  apparently  any  regular  arrangement.  Drawings  196  and  197  exhibit 
magnified  views  of  scales  taken  from  the  wing  of  a  butterfly,  known  by  the 
name  of  the  Morpho  Menelaus.  The  color  of  the  upper  surface  of  its  wing  is 
of  a  rich  blue,  brilliant  beyond  description,  and  vying  in  splendor  with  the  purest 
azure  of  the  sky.  The  scales  taken  from  the  central  portions  are  of  a  pale  blue 
tint,  mingled  with  others  that  are  almost  black.  The  former  are  for  the  most 
part  wider  than  the  latter,  and  measure  nearly  the  one  hundred  and  twentieth 
part  of  an  inch  in  length.  Beneath  the  microscope  they  exhibit  the  appearance 
presented  in  drawing  196  ;  the  entire  surface  being  fluted  with  lines  which  run 
lengthwise  of  the  scale,  and  are  connected  together  by  short  cross  lines  passing 
between  them.  In  drawing  198  and  199  are  delineated  the  feathers  of  the 
lead-colored  Spring-tail,  an  active  little  insect  about  the  tenth  of  an  inch  long, 


124 


VIEWS    OF    THE    MICROSCOPIC    WORLD. 


found  among  saw-dust  and  damp  wood.  Its  body  and  limbs  arc  cased  in  deli- 
cate scales,  varying  from  one-nine  hundredth  to  one-one  hundred  and  sixtieth 
part  of  an  inch  in  length  ;  and  which  are  covered  with  lines  diversified  in  ar- 
rangement as  displayed  in  the  above-named  figure.  Scales  of  very  singular  form 
are  found  on  the  under  side  of  the  wing  of  a  beautiful  blue  butterfly,  called  the 
Lycoena  Argus.  In  shape  they  resemble  a  battledore,  with  strings  of  beads  run- 
ning lengthwise  over  the  surface  parallel  to  each  other.  The  feathers  upon  the 
wing  of  an  insect  are  exceedingly  numerous,  for  according  to  Leuwenhoeck  each 
wing  of  the  moth  of  the  silkworm  contains  more  than  two  hundred  thousand, 
and  the  wing  of  this  insect  is  small  compared  with  that  of  many  other  moths  ; 
for  one  of  the  largest,  the  Atlas  moth,  the  feathers  of  which  are  delineated  in 
figure  200,  measures  nearly  a  foot  across  the  wings.  In  figure  201  is  delineated 


Fig.  200. 


Fig.  201. 


several  scales  from  the  wing  of  the  Death's-head  moth,  which  receives  its  name 
from  bearing  upon  the  surface  of  its  thorax  a  large  grey  or  yellowish  spot,  which 
strongly  resembles  in  form  the  front  view  of  a  human  skull  or  Death's  head. 
On  account  of  this  peculiarity,  and  also  from  its  great  size,  and  the  power  it  like- 
wise possesses  of  emitting  a  plaintive  cry,  this  insect  has  been  regarded  with 
superstitious  awe.  Reaumur  relates,  that  appearing  once  in  great  numbers  in 
some  districts  of  Bretagne,  they  were  viewed  with  terror  by  the  inhabitants, 
as  the  sure  precursor,  and  even  the  cause,  of  war  and  pestilence.  In  German 
Poland  it  is  termed  the  Wandering  Death  Bird  ;  and  to  the  dreamy  imaginations 
of  the  superstitious,  the  head  of  a  perfect  skeleton  is  distinctly  visible  on  the  insect, 
resting  upon  the  limb  bones  crossed  beneath ;  while  its  cry  is  the  moaning  of  a  child 
in  pain  and  suffering.  Its  creation  is  regarded  as  the  work  of  evil  spirits,  and  the 
reflections  of  those  lurid  flames  amid  which  it  arose,  are  discerned  in  the  gleaming  of 
its  glittering  eyes.  The  rich  hues  of  the  scales  of  the  Lepidoptera  are  supposed  in 
general  to  be  due  to  the  presence  of  coloring  matter,  but  the  more  delicate  tints 
are  regarded  by  Dr.  Roget  as  an  optical  effect,  produced  by  the  fine  lines  upon 
the  surface  of  the  scale  ;  a  phenomenon  identical  with  that  observed  in  mother  of 
pearl,  where  the  concentric  flutings  of  the  shell  occasion  the  brilliant  play  of 
colors  that  adorn  its  surface. 


PARTS    OF    INSECTS,    AND    MISCELLANEOUS    OBJECTS.  125 

EGGS. — The  eggs  of  birds,  though  differing  in  color,  possess  nearly  the  same 
form,  varying  only  by  slight  changes  between  an  oval  and  a  globular  shape.  Such 
however  is  not  the  case  with  those  of  insects,  which  exhibit  an  endless  variety 
of  exquisite  forms  often  most  beautifully  and  elaborately  wrought,  and  bearing  a 
resemblance  to  richly  carved  work.  "  We  meet  with  them,"  says  Kir  by,  "  of  the 
shape  of  the  common  hen's  egg,  flat,  round,  elliptical,  conical,  cylindrical,  hemi- 
spherical, pyramidal,  square,  lens-shaped,  turban-shaped,  pear-shaped,  boot-shaped, 
and  sometimes  of  shapes  so  strange  and  peculiar,  that  we  can  scarcely  credit  their 
claim  to  the  name  of  eggs."  Indeed,  the  empty  shells  left  upon  the  leaves  of 
plants  have  been  mistaken  for  minute  flower  cups,  and  according  to  Reaumur 
were  once  actually  thus  delineated  by  a  naturalist,  who  was  extremely  perplexed 
to  account  for  the  origin  of  these  singular  blossoms.  Among  the  most  rich  and 
elegant  forms,  are  those  which  belong  to  the  eggs  of  butterflies,  the  surface  being 
often  exquisitely  sculptured  and  profusely  adorned  with  ornaments.  Four  varie- 
ties are  delineated  in  drawings  202  and  203  as  they  appear  when  highly  magnified. 

Fig  202.  Fig.  203. 


In  this  group,  a  202,  is  the  egg  of  a  butterfly  called  the  Hipparchia  Tithonus  ;  it 
is  of  a  dome-shaped  form,  strengthened  and  adorned  with  longitudinal  ribs,  sym- 
metrically arranged  and  connected  by  cross  lines;  c  203,  is  the  egg  of  another 
kind,  the  Hipparchia  Furtina,  and  is  crowned  at  the  top  with  circular  rows  of 
scales,  overlapping  each  other  likes  the  plates  of  armor  or  the  scales  of  fishes. 
The  same  type  is  observed  in  the  egg  of  the  Noctua  Nupta,  at  figure  b  202, 
where  the  end  of  the  egg  is  presented  to  view ;  and  towards  which  numerous 
strongly  defined  ridges  converge.  Between  these  ridges  the  surface  is  deeply 
fluted.  The  eggs  of  many  insects  are  provided  with  a  small  lid  or  cover,  which 
when  the  young  insect  within  has  arrived  at  maturity  it  throws  off  at  its  will, 
and  emerging,  through  the  opening  thus  made,  from  the  enclosing  shell,  enters  at 
once  upon  its  new  state  of  existence.  In  addition  to  this  provision,  a  curious 
contrivance  is  found  in  the  egg  of  a  certain  species  of  bug,  and  which  is  shown 
at  d  203.  It  consists  of  a  horny  substance  in  the  shape  of  a  cross-bow,  the 
bow  being  attached  to  the  lid,  and  the  handle  to  the  upper  end  of  the  side  of 
the  egg.  It  is  supposed  to  be  designed  to  facilitate  the  egress  of  the  young  when 
it  is  ready  to  leave  the  shell. 

HAIRS. — The  hairs  of  different  animals  afford  beautiful  objects  for  microscop- 
ical examination.  Those  of  the  common  mouse  which  are  shown  in  drawings  204 


126 


VIEWS    OF    THE    MICROSCOPIC    WORLD. 


and  205,  vary  in  form  and  size,  their  diameters  ranging  from  one-two  thousandth 
to  one-three  hundredth*  of  an  inch.     The  chief  van- 
Fig.  204.  Fig.  205.        eties  are  here  exhibited  of  their  relative  sizes  in  figures 
204  a  and  6,  and  205  a,  and  are  delineated  as  they 
are  seen  by  transmitted  light ;  the  real  diameter  of 
the  hair  in  cut  204  a,  is  only  the  sixteen  hundredth  part 
of  an  inch.     When  the  hairs  are  viewed  by  reflected 
light,  their  appearance  is  changed,  for  the  solid  parts 
then  reflect  more  light  than  the  transparent,  and  appear 
white,  while  the  transparent  portions  are  comparatively 
dark.     The  appearance  presented  by  a  magnified  hair 
when  viewed  by  reflected  light  is  shown  in  figure  205 
b.    The  hair  of  the  bat  is  different  from  that  of  the  mouse,  and  consists  of  many 
varieties  distinguished  from  each  other  in  form  and  structure.     The  two  prin- 
cipal kinds  are  delineated  in  figures  206  and  207.   The  first  represents  a  collection 


Fig.  206. 


207.      209.      208. 


of  hairs  scattered  promiscuously  together,  each  possessing  a  figure  like  that  which 
would  be  formed  by  a  series  of  cones  with  the  points  of  each  inserted  into  the 
middle  of  the  base  of  another.  The  second  exhibits  a  curious  spiral  struc- 
ture. Figure  208  is  a  white  hair  from  a  young  cat;  figure  209  that  of 
a  Siberian  fox,  and  210,  the  hair  of  a  common  caterpillar,  which  divides  into 


Fig.  210. 


branches ;  but  the  form  of  these  hairs  is  different  for  every  species  of  caterpillar  ; 
in  some  they  resemble  the  spreading  plumes  of  the  peacock's  tail,  while 
others  are  adorned  with  delicate  tufts  of  hair,  and  bristle  with  thorns. 


PARTS    OF    INSECTS,    AND    MISCELLANEOUS    OBJECTS.  127 

THE  PROBOSCIS  OF  THE  OX-FLY. — This  insect,  which  is  the  torment  of  cattle 
during  the  summer  months,  and  nourishes  itself  upon  their  blood,  is  provided 
with  a  curious  apparatus  admirably  adapted  for  piercing  the  tough  hide  and  im- 
bibing the  blood  of  its  victim.  The  proboscis  is  shown,  of  its  natural  size,  in 
figure  211 ;  and  a  magnified  view  of  the  same  is  presented  in  figure  212. 

This  member  is  complex  in 
its  structure,  and  is  enclosed 
in  a  fleshy  case,  which  is  re- 
moved in  the  drawing,  in  or- 
der that  the  several  parts  may 
be  separately  exhibited.  The 
parts  are  six  in  number,  be- 
sides the  two  feelers,  a,  a, 
which  are  composed  of  a  spon- 
gy substance,  fringed  with  hair. 
They  are  of  a  gray  color,  and 
are  capable  of  motion,  each 
being  furnished  with  a  joint,  Fig<2ii. 
at  the  point  where  it  is  con- 
nected with  the  head. 

The  office  of  these  append- 
ages is  to  protect  from  harm 
the  delicate  parts  of  the  pro- 
boscis, since  they  are  always 

placed  on  each  side  of  it  whenever  a  puncture  is  made  by  the  insect.  The 
blades  or  lancets,  6,  6,  are  the  instruments  which  inflict  the  wound :  in  shape 
they  are  alike,  each  having  the  form  of  a  broad  knife  with  a  sharp  point  and 
fine  edge,  and  gradually  increasing  in  thickness  towards  the  back.  The  parts, 
c,  c,  termed  piercers,  are  furnished  with  teeth  like  a  saw,  and  are  supposed  to  be 
employed  for  the  purpose  of  increasing  the  size  of  the  wound,  and  thus  obtain- 
ing a  more  copious  supply  of  blood.  It  is  also  imagined,  from  being  of  a  hard 
texture,  that  they  likewise  serve  as  a  protection  to  the  tube  which  conveys  the 
blood  from  the  wound  to  the  stomach  of  the  insect,  and  which  would  otherwise 
be  liable  to  receive  injury.  This  tube  is  seen  inclosed  in  its  fleshy  case,  d,  with 
a  lancet  and  serrated  piercer  upon  either  side. 

THE  SUCKER  OF  THE  GNAT. — The  sucker  of  the  gnat  appears  to  the  naked 
eye  like  a  sharp  needle,  finer  than  a  hair,  but  under  the  microscope  it  presents 
a  complicated  structure ;  and  although  it  has  been  minutely  examined,  the  most 
distinguished  observers  have  differed  in  respect  to  the  number  of  parts  of  which 
it  is  composed.  Leuwenhoeck  enumerates  four  parts,  Swammerdam  six,  inclu- 
ding the  lip,  and  Reaumur  Jive  ;  but  it  has  been  supposed  that  their  observations 
might  possibly  have  been  made  either  upon  mutilated  insects,  or  upon  those  of 
different  species.  As  soon  as  a  gnat  has  settled  upon  some  exposed  part  of  an 


128 


VIEWS    OF    THE    MICROSCOPIC    WORLD. 


Fig.  213. 


animal,  it  puts  forth  from  the  sheath  of  its  sucker  a  fine  point,  with  which  it 
pierces  the  skin.  This  point  was  regarded  by  Swammerdam  as  single,  inasmuch 
as  he  was  unable  to  discern  the  least  breadth  at  the  extremity,  under  the  best 
microscopes  at  his  command,  but  both  Leuwenhoeck  and  Reaumur  discovered  it 
to  consist  of  several  needles,  some  of  them  barbed  and  serrated. 

In  fact,  the  compound  structure  is  revealed  upon  pressing  the  piercer  between 
the  finger,  when  the  several  parts  separate  from  each  other.  These  fine  needles 
are  inclosed  in  a  sheath  formed  of  some  yielding  substance,  and  divided  through- 
out its  whole  length  ;  and  not  only  does  it  shield  these  slender  instruments  from 

injury,  but  also  serves  to  sup- 
port and  steady  them  during 
the  operation  of  penetrating 
the  skin ;  answering  the  same 
purpose  as  the  fleshy  pro- 
tuberances in  the  proboscis  of 
the  ox-fly.  The  sheath  is  also 
supposed  by  Swammerdam 
to  be  employed  as  a  tube, 
through  which  the  insect  im- 
bibes the  blood  that  flows  from 
the  wound. 

A  magnified  view  of  the 
several  parts  is  exhibited 
in  cut  213,  where  a  re- 
presents the  sucker  in  its 
sheath  ;  b,  half  of  the  sheath 
broken  off,  in  order  to  show 
the  sucker  ;  and  c,  the  barbed 
point  of  one  blade  of  the 
sucker.  In  cut  214,  the  sucker 
is  displayed  so  as  to  exhibit 
its  component  parts. 

THE  PROBOSCIS  OF  THE  BEE. — The  exquisite  instrument,  by  which  the  bee  col- 
lects from  the  flowery  realm  the  rich  nectareous  food  that  is  necessary  for  its 
support,  is  a  most  elaborate  structure,  and  every  part  admirably  subserves  the 
purposes  for  which  it  was  made.  It  has  been  most  carefully  analyzed  both  by 
Reaumur  and  Swammerdam  ;  and  the  latter  observer  was  so  struck  with  the 
proofs  of  wisdom  and  benevolent  design,  revealed  in  this  minute  member,  that 
at  the  close  of  his  investigation  he  breaks  forth  into  the  following  pious  strain : 
"  I  cannot  refrain  from  confessing,  to  the  glory  of  the  Incomprehensible  Archi- 
tect, that  I  have  but  imperfectly  described  and  represented  this  small  organ  ;  for 
to  represent  it  to  the  life  in  its  full  perfection,  as  truly  most  perfect  it  is,  far  ex- 
ceeds the  utmost  effort  of  human  knowledge." 


PARTS    OF    INSECTS,    AND    MISCELLANEOUS    OBJECTS. 


129 


The  proboscis  of  the  bee  is 
shown  of  its  natural  size  in 
figure  215,  and  a  magni- 
fied view  of  the  same  is  pre- 
sented in  figure  216.  It  is 
here  seen  to  consist  of  five  dis- 
tinct parts,  the  central  stem, 
a,  6,  called  the  tongue,  and 
four  other  parts  arranged  in 
pairs,  constituting  two  sheaths. 
The  exterior  sheath  is  formed 
of  the  two  branches,  /,  n,  <7,  k,  f 
and  e,  o,  A,  I ;  and  the  interior 
.of  the  parts  c,  r,  #,  and  c?,  s,  v. 
These  sheaths  are  composed  of 
a  horny  substance,  are  fringed 
with  hair,  and  provided  with 
joints ;  and  fold  down  upon  the 
tongue  one  over  the  other, 
forming  together  in  appear- 
ance a  single  tube,  convex  out- 
ward, and  concave  inward,  to- 
wards the  trunk  of  the  bee. 
The  articulations  of  the  outer 
sheath  are  at  g  and  A,  and  the 
parts  above,  which  in  the  fig- 
ure are  widely  separated,  can 
be  folded  down  at  pleasure 
upon  the  central  stem,  by 
means  of  these  joints.  The 
branches  of  the  interior  sheath  are  each  possessed  of  three  joints,  the  lower  jointed 
portion  being  longer  than  either  of  the  other  two,  which  are  always  kept  curved 
outwards,  as  represented  in  the  figure  at  d  and  c,  even  when  the  complex 
apparatus  is  closed  as  much  as  possible.  It  is  supposed  by  Swammerdam,  that 
these  fringed  joints  aid  the  bee  in  the  manner  of  fingers  by  opening  those  flower- 
cups  that  but  partially  reveal  their  sweets,  and  removing  obstructions  that  would 
otherwise  prevent  the  tongue  from  reaching  the  inmost  recesses  of  the  blossom^ 
The  upper  part  of  the  tongue  consists  of  rings,  fringed  with  circles  of  hair,  and 
it  terminates  in  a  small  knob,  which  is  also  fringed.  The  office  of  the  hair  is  to 
brush  off  and  secure  the  honey  discovered  by  the  insect  in  the  flower-eells. 
The  lower  part  of  the  tongue  is  membranous  in  its  structure,  and  can  be 
greatly  distended,  and  when  the  bee  is  collecting  its  food,  form  a  capacious  bag 
for  the  sweet  juices,  that  are  ultimately  converted  into  honey.  The  insect 
gathers  its  treasures  by  lapping  them  up  with  this  complex  instrument  from  the 

9 


Fig.  215. 


130 


VIEWS    OF    THE     MICROSCOPIC    WORLD. 


nectaries  of  flowers,  sweeping  with  equal  facility  the  round  or  the  concave  surface  of 
the  leaves.  When  a  sufficient  portion  is  thus  collected,  it  is  first  deposited  in 
the  reservoir  just  mentioned,  and  thence  conveyed  to  the  honey -stomach.  As 
soon  as  the  bee  has  rifled  a  blossom  of  its  honey,  the  several  branches  of  its  pro- 
boscis are  quickly  folded  together  to  protect  the  more  delicate  parts  from  injury, 
and  when  it  is  again  to  be  employed,  they  are  as  rapidly  again  expanded.  While 
at  rest  it  is  doubled  up  by  means  of  a  joint,  one  branch  being  brought  within 
the  lip,  and  the  second  secured  beneath  the  head  and  neck. 


Fitj.  217. 


STING  OF  THE  WILD  BEE. — The  sting  of  the  wild  bee,  with  its  several  parts, 

is  delineated  in  figure  217,  copied  from  an  en- 
graving of  the  drawings  of  Mr.  Newport,  who  ex- 
amined and  dissected  this  organ  with  the  utmost 
care  and  describes  it  as  follows  :  "  The  sting  is 
formed  of  two  portions  placed  laterally  together, 
but  capable  of  being  separated  :  b  is  the  sting, 
the  point  of  which  is  bent  a  little  upward,  and 
becomes  curved,  as  shown  at  d,  where  the  barbs 
are  exhibited  more  highly  magnified.  They  are 
about  six  in  number,  and  are  placed  on  the  un- 
der surface,  with  their  points  directed  backwards. 
At  the  base  of  the  sting,  e,  there  is  a  semi-cir- 
cular projection,  apparently  for  the  purpose  of 
preventing  the  instrument  from  being  thrust  too 
far  out  of  the  sheath  in  which  it  moves  ;  it  has 
likewise  a  long  tendon  to  which  the  muscles  are 
attached.  Between  these  parts,  (the  sting  and 
the  sheath,)  when  brought  near  to  each  other, 
the  venom  flows  from  the  orifice  at  the  extrem- 
ity of  the  poison-tube,  which  comes  from  the 
anterior  portion  of  the  poison-bag,  a.  This  bag 
is  of  an  oval  shape,  and  is  not  the  organ  which 
secretes  the  venom,  but  is  merely  a  receptacle 
for  holding  it,  since  it  is  conveyed  into  this  re- 
servoir by  means  of  a  long  winding  tube,  which 
receives  it  from  the  secreting  organs  at  /.  The 
tubular  sheath  of  the  sting  is  seen  at  c  ;  it  is 
open  at  its  base  and  along  its  upper  surface,  as 
semi-circular  projection  before  mentioned.  The  muscles  which  move 

are  distinct  from  those  which  give  motion  to  the  sting.     The  sting  of 

e  resembles  that  of  the  honey-bee." 

last  joint  of  the  feet  of  insects  is  usually  terminated  by  a  claw, 
either  single  or^uble,  and  in  the  case  of  spiders  it  is  divided  into  three  branches. 


the  sheath 


PARTS    OF    INSECTS,    AND    MISCELLANEOUS    OBJECTS. 


131 


A  triple  claw  of  a  spider  is  exhibited  in  figure  218 ;  the  several  hooks  are  not 
smooth,  but  are  armed  with 
teeth  on  one  side,  and  pre- 
sent quite  a  formidable  ap- 
pearance. The  length  of 
the  tooth,  a,  the  third  from 
the  end,  on  the  middle  hook, 
is  the  Jive  hundredth  part 
of  an  inch. 

By  the  aid  of  their  claws, 
insects  are  enabled  to  move 
over  rough  substances  with 
great  facility,  either  up- 
ward or  downward,  but 
upon  polished  surfaces  they 
advance  with  the  utmost 
difficulty.  Upon  the  fore- 
most pair  of  their  feet  these 
hooks  are  bent  backward, 
on  the  posterior  pair  for- 
ward, and  on  the  third  or 
middle  pair,  inward  ;  thus  rendering  the  position  of  the  insect  exceedingly  sta- 
ble, and  effectually  securing  it  from  displacement.  The  claws  are,  therefore, 
highly  useful  to  the  insect,  either  in  a  state  of  rest  or  activity.  On  the  feet  of 
the  larger  kinds  of  insects,  cushions,  composed  of  thick  tufts  of  fine  hair,  are 
found,  which  prevent  it  from  receiving  injury  upon  leaping  from  a  considerable 
height.  Moreover,  these  delicate  and  elastic  hairs  adapting  themselves  to  the 
asperities  on  the  bodies  which  the  insects  frequent,  enable  the  latter  to  adhere  to 
them  with  much  tenacity.  But  a  more  efficient  apparatus  is  possessed  by  some 
of  these  little  creatures,  which  gives  them  the  power  of  walking  in  any  position 
upon  smooth  and  glassy  surfaces.  It  consists  of  suckers,  so  adapted  to  the  foot, 
that  the  insect  is  sustained  by  the  pressure  of  the  air  upon  the  sucker. 

The  sucker  consists  of  a  thin  membrane,  capable  of  expansion  and  contrac- 
tion, having  the  edges  serrated  or  notched,  so  that  it  can  be  made  to  fit  closely 
to  surfaces  of  every  shape.  The  sucker  acts  in  precisely  the  same  manner  as 
the  circle  of  leather  with  a  string  attached  to  the  centre,  which  lads  use  in  their 
sports  to  take  up  stones  and  pebbles,  the  leather  being  first  wetted  in  order  to 
make  it  adhere  closely  to  the  stone.  The  common  house-fly  has  two  suckers  to 
each  foot,  immediately  under  the  root  of  the  claw,  and  attached  by  a  narrow 
neck  capable  of  motion  in  all  directions.  These  appendages'  are  delineated  in 
figure  219,  which  represents  the  suckers  on  the  under  side  of  the  foot  of  a  blue- 
bottle fly,  with  the  claws  of  the  insect  branching  over  them.  In  the  horse-fly, 
every  foot  is  provided  with  three  suckers ;  and  in  the  yellow  saw-fly,  four  are 
arranged  along  the  under  surface  of  the  toes,  one  upon  each  of  the  four  first 


132 


VIEWS    OF    THE    MICROSCOPIC    WORLD. 
Fig.  219.  Fig.  220. 


Fig.  221. 


Fig.  222. 


joints,  as  in  figure  220.  In  a  species  of  water-beetle,  the  male  insect  is  alone 
provided  with  a  numerous  collection  of  suckers.  The  first  three  joints  of  the 
feet  of  the  fore-legs,  have  the  form  of  a  shield,  the  under  surface  of  which 
is  covered  with  suckers,  some  very  large,  others  small,  and  a  third  class  exceed- 
ingly minute,  all  provided  with  long,  hollow  stems.  Several  of  the  smallest  kind 
are  exhibited  in  figure  221,  highly  magnified,  and  having  the  appearance  of  mush- 
rooms with  the  cups  inverted.  The  corresponding  joints  of  the  second  pair  of 
feet,  are  likewise  studded  on  the  under  side  with  a  vast  number  of  minute  ap- 
pendages of  this  character. 

A  certain  species  of  grasshopper,  called  the  Acridium  biguttulum,  is  fur- 
nished with  a  large  oval  sucker,  which  is  placed  between  the  claws  beneath  the 
last  joint  of  the  foot.  The  first  joint  is  padded  on  the  lower  side  with  three  pairs, 
and  the  second  with  one  pair  of  cushions.  These  cushions  are  filled  with  an  elastic 
fibrous  substance,  the  texture  of  which  is  looser  towards  the  margin,  in  order  to 
increase  the  elasticity.  The  several  parts  are  displayed  in  figure  222.  By  the 
aid  of  this  singular  apparatus,  insects  are  enabled  to  traverse  with  the  greatest 
facility  the  smoothest  surfaces,  in  an  inclined,  vertical,  or  inverted  position. 
Thus  a  fly  is  seen  to  walk  upon  a  mirror,  a  ceiling,  or  the  under  surface  of  a  pane 
of  glass,  with  as  much  ease  and  security  as  upon  the  top  of  a  table.  Indeed, 
when  inverted,  the  weight  of  the  fly  causes  the  sucker  to  adhere  more  firmly 
than  in  any  other  position  ;  inasmuch  as  the  weight  of  the  insect  tends  to  draw 
down  the  sucker  and  to  increase  the  vacuum  beneath  it,  and  thus  to  render  the  pres- 
sure of  the  atmosphere  upon  the  sucker  proportionally  greater.  To  this  fact  .has 
been  attributed  the  circumstance,  that  flies  congregate  upon  the  ceiling  and  re- 
pose there  during  the  night,  since  the  pressure  of  the  air  upon  the  membrane  of 
the  suckers  fixes  them  firmly  in  their  resting-place,  without  any  voluntary  effort. 

ANTENNAE. — This  name  is  given  to  certain  curious  organs  possessed  by  insects 
and  crustaceous  animals  ;  the  majority  of  the  latter  class  being  endowed  with  four, 
while  no  insect  has  more  than  one  pair.  They  are  inserted  in  the  head,  and,  ex- 
cept where  the  insect  has  four  eyes,  are  either  placed  in  the  space  between  the 
eyes,  or  in  that  immediately  beneath  them.  They  are,  for  the  most  part,  formed 


PARTS    OF    INSECTS,    AND    MISCELLANEOUS    OBJECTS.  133 

of  a  number  of  tubular  joints,  so  as  to  admit  of  motion  in  all  necessary  direc- 
tions. The  office  of  these  organs  is  not  yet  thoroughly  understood.  Many  cele- 
brated naturalists  consider  them  merely  as  feelers,  that  serve  to  guide  the  move- 
ments of  the  insect ;  while  others,  no  less  distinguished,  consider  this  office  as 
but  secondary,  and  that  the  primary  use  of  the  antennae  is  to  enable  the  insect 
to  detect  sounds — that  they  are  in  truth  organs  of  hearing.  The  forms  of  the 
antennae  are  extremely  various,  and  many  of  them  are  quite  elegant  and  beau- 
tiful. In  cut  223,  a  few  only  of  these  organs  are  delineated ;  one,  that  of 

Fig.  223. 


the  common  cockchaffer,  is  seen  expanded  like  a  hand  with  seven  fingers  ; 
another  exhibits  the  form  of  a  graceful  plume,  and  a  third  bears  some  resem- 
blance to  a  feather.  A  fourth  variety  is  thick  and  bushy,  like  the  tail  of  a  cat ; 
some  are  fringed  with  slender  arched  branches,  and  others  exhibit  the  form  of  a 
string  of  delicate  beads  studded  with  minute  tufts  of  hair.  Doubtless  the  great 
diversity,  in  form  and  structure,  which  obtains  in  these  singular  organs  is  needed 
for  the  well-being  and  enjoyment  of  the  different  little  creatures  to  which  they  be- 
long :  each  change  in  form,  size,  and  figure,  or  in  any  other  particular,  being 
subservient  to  some  wise  and  benevolent  purpose  ;  and  were  we  but  able  to  ex- 
plore the  whole  field  of  research,  we  should  be  enabled  to  trace  the  hand  of  Di- 
vinity in  every  minute  modification. 

SCALES  OF  FISHES. — The  scales  of  fishes  furnish  a  great  variety  of  beautiful 
objects  for  the  microscope  ;  their  figures  being  often  extremely  elegant,  and  pre- 
senting a  rich  diversity  of  forms.  For  not  only  are  different  fishes  possessed  of 
different  shaped  scales,  but  those  that  belong  to  the  same  fish  vary  in  structure, 
according  as  they  are  found  on  one  or  another  part  of  the  body.  Leuwenhoeck 
supposed  that  each  scale  was  composed  of  a  vast  number  of  minute  scales,  in  rows, 
one  layer  overlapping  another,  the  largest  being  next  to  the  fish,  and  the  rest 
gradually  diminishing  in  size  ;  thus  forming  successive  strata  from  the  base  to 
the  upper  edge  of  the  scale.  In  some  scales,  when  viewed  by  the  microscope,  a 


134 


VIEWS    OF    THE    MICROSCOPIC    WORLD. 


great  number  of  concentric  flutings  and  grooves  are  discerned,  too  fine  and  too  near 
each  other  to  be  distinctly  counted,  which  are  formed  by  the  edges  of  the  strata; 
each  line  denoting,  as  is  supposed,  the  margin  of  each  stratum  and  the  different 
stages  of  growth  in  the  scale.  These  flutings  are  often  crossed  by  others  pro- 
ceeding from  the  central  portion  of  the  scale,  and  terminating  at  the  circumfer- 
ence. The  next  twelve  figures  exhibit  the  structure  of  the  scales  of  several  fishes, 
most  of  them  well  known.  In  figure  224,  is  delineated  the  scale  of  a  species  of 

Fig.  225. 


Pig  2524. 


PARTS    OF    INSECTS,    AND     MISCELLANEOUS    OBJECTS.  135 

parrot-fish  of  its  natural  size  ;  and  in  figure  225  the  same  is  shown,  as  it  ap- 
pears when  considerably  magnified.  The  position  of  each  layer  is  here  indicated 
by  the  numerous  waving  lines  that  cover  the  surface  of  the  scale,  and  the  ribs 
and  flutings  which  branch  out  from  the  middle  portions,  are  very  strongly  marked. 

Fig.  226. 


Fig.  227. 

Figures  226  and  227,  represent  the  scale  of  the  sea-perch,  both  magnified  and 
of  its  natural  size.  This  scale  is  broader  in  proportion  to  its  length  than  that 
of  the  parrot-fish,  and  unlike  the  latter,  is  destitute  of  the  radial  divisions.  The 
edges  also  of  the  component  strata,  as  seen  in  the  magnified  figure,  are  not 
bounded  by  curved  lines,  but  are  serrated,  presenting  an  appearance  like  the 
teeth  of  a  saw.  The  lower  part  of  the  scale  is  likewise  notched  along  the  edges, 
which  gradually  approach  each  other,  and  unite  at  the  base. 

A  scale  of  the  haddock  is  delineated  in  figures  228  and  229,  in  the  first  of  which 
it  appears  of  its  natural  size,  and  the  other  displays  a  magnified  view  of  the  same. 


136 


VIEWS    OF    THE    MICROSCOPIC    WORLD. 


Fig.  229. 


Fig.  228. 


It  is  a  beautiful  scale,  resembling  a  shield  in  form, 
and  the  entire  surface  is  covered  with  numer- 
ous radial  lines  crossing  the  concentric  strata. 

A  scale  of  the  roach  is  exhibited  of  its  na- 
tural size  in  figure  230,  and  the  same  magnified 
is  shown  in  figure  231.  It  is  seen  to  differ 
from  all  the  preceding  scales  in  many  particu- 
lars. The  broad  flutings  rise  fan-shaped  from 
the  centre  of  the  scale,  flanked  on  either  side  by 
numerous  concentric  lines,  which  indicate  the 
position  of  the  edges  of  the  overlapping  strata. 
These  lines  do  not  terminate  at  the  extreme  ra- 
dial branches,  but  pass  across  them  as  in  the  case 
of  the  parrot-fish.  The  lower  portion  of  the 
figure,  which  is  apparently  covered  with  teeth, 
represents  the  root  of  the  scale,  by  which  the 
latter  is  attached  to  the  fish.  The  distance,  a, 
6,  between  two  of  the  radial  lines,  as  measured 
by  the  micrometer,  is  one-fiftieth  part  of  an 
inch. 

In  figure  232  and  233,  another  scale  is  shown, 
both  in  its  real  and  magnified  dimensions.  It  is 
the  scale  of  the  flounder,  and  resembles  in  some 
points  that  of  the  roach.  The  series  of  concentric 


lines  on  each  side,  crossing  the  radial  divisions,  are  mainly  alike,  and  the  fan-like 
flutings  are  seen  in  both,  only  their  divergence  is  far  greater  in  the  scale  of  the 
roach  than  in  that  of  the  flounder.  Owing  to  this  circumstance  the  forms  of 
the  scales  are  different,  that  of  the  roach  being  broader  than  it  is  long — while  in 
the  case  of  the  flounder,  the  length  exceeds  the  breadth.  The  distance  between 
two  of  the  radical  lines,  a  and  6,  in  figure  233,  is  the  one-three  hundred  and 
tenth  part  of  an  inch. 

Figure  234  is  a  magnified  portion  of  the  skin  of  a  sole-fish,  viewed  by  re- 
flected light — the  dark  ground  representing  the  skin,  and  the  lighter  parts  the 
upper  protruding  portions  of  the  scales,  which  exhibit  a  beautifully  serrated  ap- 
pearance. Figure  235  is  the  same,  of  its  natural  size. 

THE  INTERNAL  ORGANS  OF  RESPIRATION  OF  THE  SILK- WORM. — The  mode  in 
which  insects  respire,  is  very  different  from  that  which  exists  among  the  higher  or- 
ders of  animals.  They  are  not  possessed  of  lungs,  neither  do  they  breathe  through 
the  mouth ;  but  inhale  the  air  through  numerous  orifices,  called  spiracles,  with 
which  are  connected  respiratory  tubes,  that  extend  in  minute  ramifications  to  every 
part  of  the  body.  These  tubes,  which  are  divided  into  two  classes,  consist  of 
three  coatings.  The  first,  or  external  envelope,  is  a  membrane  comparatively 
thick,  strengthened  by  a  great  number  of  fibres,  which  form  around  it  numer- 


PARTS    OF    INSECTS,    AND    MISCELLANEOUS    OBJECTS. 
Fig.  231. 


137 


Fig.  230. 


ous  irregular  circles.  The  second  tunic  is  a  tissue  more  delicate  and  transparent, 
and  the  third  is  formed  of  a  cartilaginous  thread,  wound  spirally  upon  itself.  In 
figure  236,  are  exhibited  portions  of  the  respiratory  tubes  of  the  silk-worm,  con- 
siderably magnified.  The  fibrtms  structure  is  at  once  perceived,  and  the  end 


138 


VIEWS    OP   THE    MICROSCOPIC    WORLD. 
Fig.  233. 


Fig.  232. 

of  a  spiral  thread  is  seen  at  a,  the  thickness  of  which  measures  only  one-fifteen 
thousandth  part  of  an  inch.  The  breathing  tubes,  with  the  branches  into  which 
they  subdivide,  are  very  numerous  in  some  insects,  amounting  to  more  than 
eighteen  hundred,  and  the  ramifications  become  at  length  so  exquisitely  fine, 
that  the  most  powerful  lenses  fail  to  detect  them. 

MAGNIFIED  FLEA. — This  wonderfully  active  little  creature,  is  delineated  in  draw- 
ing 237,  as  it  appears  under  a  moderately  magnifying  power.  The  head  (1)  is 
small,  and  covered  with  a  shelly  plate,  and  on  either  side  gleams  a  brilliantly 
dark  eye,  (2)  the  pupil  of  which  is  encircled  with  an  iris  of  a  greenish  hue.  Be- 


PARTS    OF    INSECTS,    AND    MISCELLANEOUS    OBJECTS. 


139 


Fig.  235. 


Fig.  234. 

hind  the  eyes  are  two  small  cavities  fringed  with  hairs,  and  which  are  supposed 
to  be  the  ears.  Below  the. head  at  3,  are  seen  three  jointed  members,  which 
are  the  feelers  and  piercer  of  the  insect.  The  piercer  consists  of  a  tube  and 
tongue,  and  on  each  side  of  the  latter  is  a  sharp  lancet-like  blade,  with  which 
the  flea  punctures  the  skin  of  its  victim. 

The  anterior  pair  of  legs  are  shown  at  4  and  5  ;  at  figure  6,  are  seen  the  mid- 
dle pair,  and  the  third  pair  are  extended  under  the  body  of  the  insect.  These 
last  double  up  their  several  parts  together,  like  the  foot,  leg,  and  thigh  of  a  man. 
All  the  legs  are  fringed  with  hair,  and  are  terminated  by  claws.  In  order  to  leap, 
the  flea  folds  up  its  six  legs,  and  tben  instantaneously  extending  them,  makes 
its  spring,  exerting  its  whole  strength  at  one  effort.  The  body  of  the  insect  is 
encased  in  an  envelope  consisting  of  overlapping  plates,  symmetrical  in  form  and 
arrangement.  Along  the  back  and  under  the  belly,  the  plates  are  studded  with 
hairs,  equally  distant  from  each  other,  and  ranged  in  a  line  along  the  middle  of 
the  plate.  The  distance  between  two  contiguous  hairs  in  the  same  row,  is  about 
one-jive  hundredth  part  of  an  inch.  The  plates  near  the  head,  are  likewise 
fringed  with  hairs, 


140 


VIEWS    OF    THE    MICROSCOPIC    WORLD. 
Fig.  236. 


The  strength  of  the  flea  is  very  great ;  for  at  the  fair  of  Oharlton  in  Kent,  in 
the  year  1830,  a  man  exhibited  three  fleas  harnessed  to  a  carriage  fifty  times 
their  own  bulk,  which  they  pulled  along  with  great  ease ;  another  pair  drew  a 
carriage,  and  a  single  flea  a  brass  cannon. 

A  MITE  MAGNIFIED. — Upon  carefully  viewing  with  the  -naked  eye  the  fine  dust 
of  figs,  or  decayed  portions  of  old  cheese,  round,  living  specks  will  frequently  be 
seen,  moving  slowly  and  with  difficulty  among  the  atoms  by  which  they  are  sur- 
rounded. These  specks  have  received  the  name  of  mites,  and  are  so  small  that 
they  easily  elude  observation.  When  magnified  under  the  solar  microscope,  their 
images  are  seen  moving  around  upon  the  screen,  endeavoring  to  avoid  the  glare  of 
the  light.  They  then  appear  of  considerable  dimensions,  and  their  several  mem- 
bers and  parts  are  distinctly  revealed.  A  magnified  mite  is  delineated  in  figure 
238.  Each  of  its  numerous  legs  are  seen  to  consist  of  several  joints ;  its  body 
is  oval,  tapering  towards  the  head,  which  is  furnished  with  antennas,  and  its 
surface  is  covered  with  numerous  long  and  slender  hairs.  It  is  naturally  a  dis- 
gusting creature,  and  the  unpleasant  associations  connected  with  it  render  it  still 
more  so. 

GLOBULES  OF  BLOOD. — When  a  drop  of  flowing  blood  is  taken  from  the  veins 
of  an  animal  and  spread  over  a  glass  slide,  it  is  seen  to  consist  of  a  fluid,  to- 
gether with  numerous  rounded  particles  termed  globules.  These  globules  enable 
the  observer  to  detect  the  motion  of  the  blood,  to  establish  the  fact  of  its  circula- 


PARTS    OF    INSECTS,    AND    MISCELLANEOUS    OBJECTS. 
Fig.  238. 


HI 


tion,  and  to  mark  its  course  as  it  speeds  along  through  the  arteries  and  veins. 
The  globules  are  very  abundant  in  the  blood,  each  drop  being  filled  with  many 
thousands,  and  yet,  small  as  they  are,  they  have  been  accurately  studied  and  ex- 
amined. They  are  divided  into  three  kinds,  the  red  and  white  globules,  and  other 
smaller  atoms,  which  have  received  the  name  of  molecules.  The  red  globules  far 
excel  the  white  in  number,  and  appear,  as  they  roll  through  the  centre  of  the  blood- 
vessels, to  constitute  the  greater  portion  of  the  fluid. 

In  man  and  in  most  Mammalia,  these  atoms  possess  a  round,  flattened  form, 
like  that  of  a  coin,  with  a  slight  depression  towards  the  centre.  The  position 
of  this  depression  is  indicated  by  a  dark  spot,  and  its  depth  depends  upon  the 


142  VIEWS   OF    THE    MICROSCOPIC    WORLD. 

magnitude  of  the  globule.     In  figure  239,  the  red  disks  of  the  human  blood  are 
Fig  239  delineated  as  they  are  revealed  when  subjected  to  a  high 

magnifying  power.     They  are  here  seen  promiscuously  scat- 
tered over  the  surface,  though  they  are  often  beheld  united 
together  by  their  flat  surfaces,  and  forming  little  bead-like 
^G^^^^^O^  rows  of  crimson  atoms.     The  central  depression  is  distinctly 
Q^^Q?^^R£>$   7isible  in  the  several  atoms.     The  size  of  the  red  globules 
O^«%3§0ft0^    *s  SUDject  to  much  variation,  even  in  the  same  animal.     In 
g§  ^  Otfij?      human  blood  it  ranges,  according  to  the  best  authorities,  from 
<3>*&<3p>^       one-thirty-five  hundredth  part  of  an  inch  to  one-forty-five 
hundredth,  though    an  eminent  observer  has  found  their 
average  diameter  to  be  as  great  as  one-twenty-eight  hundredth  of  an    inch. 
Their  size  in  the  elephant  is  about  one-twenty-seven  hundredth  of  an  inch,  and 
in  the  napu-musk  deer  only  one-twelve  thousandth. 

The  blood-disks  in  birds,  reptiles,  and  fishes,  differ  from  those  of  Mammalia,  in 
being  larger,  and  their  shape  is  also  oval  instead  of  round;  moreover,  in  place  of 
being  depressed  at  the  middle,  they  swell  out  on  either  side,  owing  to  the  fact 
that  the  centre  of  the  atom  is  composed  of  matter  more  solid  than  the  other 
portions.  In  birds,  the  length  of  the  oval  disk  varies  from  one-seventeen  hun- 
dredth of  an  inch  to  one-twenty-four  hundredth,  and  the  breadth  from  one-three 
thousandth  of  an  inch  to  one-forty-eiyht  thousandth.  In  the  case  of  frogs,  the 
longer  diameter  is  about  one-thousandth  of  an  inch  in  extent,  while  in  fishes 
these  globules  are  for  the  most  part  larger  than  those  of  the  frog.  The  white 
globules  in  man  and  the  Mammalia,  are  usually  larger  than  the  red,  but  like  the 
latter,  they  differ  in  magnitude.  Their  average  size,  when  examined  in  the  blood, 
is  estimated  at  about  one-twenty-six  hundredth  part  of  an  inch.  In  the  blood  of 
reptiles,  and  in  that  of  the  frog  in  particular,  the  relation  that  exists  as  to  size  be- 
tween the  red  and  white  globules,  is  reversed ;  the  latter  being  in  these  cases 
two  or  three  times  smaller  than  the  former.  These  two  classes  of  atoms  differ 
also  in  respect  to  form,  since  the  white  blood  particle  is  always  globular  through- 
out the  whole  animal  kingdom  :  a  nucleus,  consisting  of  matter  more  solid  than 
the  rest,  is  also  found  in  the  white  globule,  instead  of  a  central  depression  as 
detected  in  the  red. 

The  third  class  of  atoms,  termed  molecules,  have  been  regarded  as  the  ele- 
ments out  of  which  the  other  two  kinds  are  formed.  They  are  found  in  great 
quantities  amid  the  blood,  existing  singly,  and  also  in  small  masses  of  an  irregular 
form.  Their  minuteness  far  surpasses  that  of  the  other  atoms,  since  they  scarcely 
ever  exceed  in  diameter  one-thirty  thousandth  part  of  an  inch. 

THE  WEB  OF  THE  FROG'S  FOOT. — When  the  web  of  a  frog's  foot  is  examined 
with  a  high  magnifying  power,  it  exhibits  a  beautifully  tesselated  ground,  inter- 
sected by  blood-vessels  and  minute  capillaries,  that  wander  over  its  surface.  In 
these  the  circulation  of  the  blood  is  distinctly  seen,  the  fluid  coursing  swiftly 
through  the  arteries,  but  moving  with  less  velocity  through  the  veins.  The  red 


FARTS    OF    INSECTS,    AND    MISCELLANEOUS    OBJECTS. 


143 


globules  appear  in  immense  numbers,  and  in  the  minute  ramifications  of  the  ves- 
sels, are  seen  rolling  along  in  single  rows,  with  here  and  there  a  white  globule 
scattered  among  them,  not  more  than  half  as  large  as  the  red  oval  disks. 

The  velocity  of  the  blood  is  not  uniform  ;  for  the  current  is  observed  to  be 
subject  to  sudden  momentary  checks,  after  which  it  again  flows  on  with  its  for- 
mer speed.  In  figure  240,  is  delineated  a  portion  of  the  web  of  a  frog's  foot, 

Fig.  240. 


magnified  three  hundred  and  fifty  diameters.  The  web  has  the  appearance  of 
mosaic  work,  being  divided  into  beautiful  hexagonal  figures  with  a  nucleus  in 
the  centre  of  each.  The  most  minute  ramifications  of  the  blood-vessels  are  here 
seen  standing  prominently  forth,  and  within  them  the  blood  globules  are  clearly 
revealed— the  large  oval  disks  representing  the  red  atoms,  and  the  small  round 
ones  the  colorless  particles.  An  idea  may  be  gained  of  the  size  of  the  capilla- 
ries by  recollecting  the  length  of  the  red  globules  in  the  blood  of  the  frog. 

^  POLLEN.— The  pollen  of  flowers  which  appears  as  a  fine  dust  to  the  unas- 
sisted eye,  is^  shown  by  the  microscope  to  be  an  assemblage  of  organized 
bodies,  possessing  regular  figures,  and  varying  in  size,  form,  and  color,  according 
as  they  are  taken  from  different  plants.  The  color  of  the  pollen  is  usually  yel- 


144 


VIEWS    OF    THE    MICROSCOPIC    WORLD. 


low ;  but  it  is  frequently  found  to  be  of  a  purple,  white,  blue,  and  brown  hue ; 
and  in  some  flowers  it  appears  in  the  form  of  clear,  transparent  grains.  The  sur- 
face of  the  particles  in  some  instances  is  smooth,  and  in  others  rough,  and  in 
many  cases  it  is  studded  with  delicate  spines  or  thorns.  The  pollen  is  contained 
in  a  receptacle  termed  the  anther,  which  at  the  proper  time  opens  and  liberates 
the  imprisoned  particles.  These  are  not  unfrequently  borne  upon  the  atmosphere 
to  a  great  distance ;  for  trees  have  been  known  to  be  fructified  by  pollen,  which 
must  have  been  wafted  through  the  space  of  three  miles.  The  number  of  par- 
ticles contained  in  each  anther,  varies  from  a  few  hundreds  to  several  thousands. 
When  the  grains  of  pollen  are  viewed  with  a  microscope,  at  the  time  they  are 
fully  matured,  they  are  seen  to  separate,  and  an  oily  liquid  flows  from  the  in- 
terior. A  similar  result  occurs  if  a  grain  of  pollen  is  thrown  upon  the  surface 
of  water.  It  there  gradually  swells  and  at  last  bursts,  when  a  liquid  escapes  from 
the  atom,  which  spreads  in  a  thin  film  over  the  surface  of  the  water  in  the  same 
manner  as  a  drop  of  oil.  This  liquid  has  been  regarded  as  the  fructifying  matter 
of  the  plant.  An  anther  of  the  mallow  is  delineated  in  figure  241,  and  the 
Fi  ^  grains  of  pollen  that  it  bears  are  indicated  by  the 

round  spots  in  the  middle  of  the  drawing.  Figure 
242,  shows  the  atoms  of  pollen  more  highly  mag- 
nified. m 

The  pollen  of  the  morning-glory 
is  delineated  in  figure  243.  It  ap- 
pears under  the  microscope  of  a 
spherical  form,  like  a  small  pea, 
with  the  surface  thickly  set  with 
minute  spines.  It  is  of  a  pearly 
white  color,  and  appears  to  be  com- 
posed of  an  assemblage  of  small  cells,  the  parti- 
tions of  which  are  indicated  by  the  light  which  passes 
through  them,  on  account  of  their  transparency ; 

and  in  the  figure  their  situation  and  mode  of  arrangement  are  distinctly  marked 
by  the  lighter  parts  of  the  drawing.  The  real  diameter  of  these  particles  of  pol- 
len is  the  one  hundred  and  twenty-fifth  part  of  an  inch. 

INDIAN  CORN. — The  pollen  of  the  Indian  corn  is  exhibited  in  figure  244.     In 
Fig.  244.          shape,  the  grains  resemble  those  of  buckwheat ;  the  central 
parts  are  thin  and  transparent,  and  are  probably  cells  filled 
with  fluid.  The  length  of  a  side  of  one  of  these  atoms  does  not 
exceed  the  eight  hundredth  and   thirtieth  part  of  an  inch, 
&  ^  G  ^  and  the  diameter  of  the  small  central  cell,  is  less  than  the 
three  thousandth  part  of  an  inch. 


PARTS    OP    INSECTS,    AND    MISCELLANEOUS    OBJECTS.  145 

FUSCHIA. — In  figure  245,  several  particles  of  the  pollen  of  the  fuschia  are 
displayed,  magnified  one  hundred  and  ten  times.  Fig.  245. 

They  are  of  a  brown  color,  and  are  similar  in  shape 
to  the  pollen  of  corn  when  viewed,  as  they  are  dif- 
fusely spread  in  their  natural  state  over  the  surface  of 
a  slip  of  glass.  But  when  they  are  immersed  in  a 
layer  of  balsam  between  two  plates  of  glass,  they  as- 
sume a  different  form,  and  little  round  appendages  are 
then  distinctly  discerned  like  handles,  at  each  corner,  as 
exhibited  in  the  figure.  One  of  the  largest  of  these 
specimens  measures  in  its  longest  extent,  the  three  hun- 
dred and  sixtieth  part  of  an  inch. 

SWEET  PEA. — The  pollen  of  the  sweet  pea  is  delinea- 
ted in  cut  246,  as  it  is  revealed  under  a  considera- 
ble magnifying  power.  It  appears  as  a  collection  of 
brown  oval  grains,  with  central  cells  of  the  same  shape, 
placed  lengthwise  of  the  grains,  and  their  positions  are  in- 
dicated by  the  light  lines  in  the  several  figures  :  the  clear 
fluid  with  which  the  cells  are  filled,  rendering  them  trans- 
parent. The  length  of  one  of  these  atoms  is  the  five 
hundredth  part  of  an  inch,  and  the  breadth  one-six  hun- 
dred and  twenty-fifth  part. 

FERN  SEED. — The  seed  of  the  fern  affords  an  interesting  object  for  the  mi- 
croscope, and  in  cut  247  a  sketch  of  various  parts  of  the  plant  is  presented, 
which  is  taken  from  Swammerdam.  a  represents  a  stalk  of  fern,  the  leaflets  of 
which  at  the  lower  part  of  the  stem  are  thickly  covered  upon  the  back  with  the 
seed-vessels  of  the  plant.  At  b  and  c,  two  of  these  seed-vessels  are  seen  highly 
magnified.  The  stalk  of  the  seed-vessel  is  smooth,  but  where  it  unites  with  the 
pods  it  changes  into  a  strong  cross-ribbed  thread,  which  completely  encircles  the 
pod  and  holds  it  firmly  together.  This  singular  cord  is  shown  at  6,  as  it  ap- 
pears edgewise,  and  in  c,  a  side  view  is  presented,  with  the  enclosed  pod,  the 
shaded  line  across  the  latter  indicating  the  position  of  a  natural  fissure  in  the 
pod.  When  the  seed  is  ripe,  the  circular  elastic  cord  is  straightened  out,  and  in 
the  process  of  unbending,  opens  the  seed-vessel,  completely  separating  it  into 
two  parts  through  the  natural  fissure,  and  forming  two  hemispherical  cups,  which 
are  attached  by  short  stems  to  the  elastic  cord.  This  stage  of  development  is 
seen  at  of,  where  the  straightened  cord  and  the  two  open  hemispherical  cups  are 
delineated.  By  imagining  the  elastic  cord  to  be  bent  back  into  its  original  shape, 
it  is  evident  that  the  edges  of  the  two  cups  would  unite,  and  that  the  figure  d 
would  re-assume  its  original  form  as  shown  at  c.  At  e  a  seed-vessel  is  shown, 
in  which  an  opening  has  been  made,  and  a  portion  of  the  enclosing  membrane 

10 


146 


VIEWS    OF    THE    MICROSCOPIC    WORLD. 
Fig.  347. 


thrown  back,  in  order  to  exhibit  the  seeds  grouped  in  their  natural  position  with- 
in the  pod.  Three  seeds,  out  of  forty,  taken  from  the  same  pod,  are  repre- 
lented  at  /,  very  highly  magnified. 


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LATIN  LESSONS.    By  GEORGE  SPENCER,  A.M. 

This  series  of  books  by  REV.  P.  BULLIONS,  D.D.,  is  used  in  nearly  or  quite  every  State  in  the 
Union.  It  is  found  to  be  precisely  adapted  to  teaching,  and  is  very  extensively  adopted 
on  the  ground  of  its  merits,  as  it  becomes  known.  The  Analytical  and  Practical  English 
Grammar  is  a  recent  and  very  popular  production  of  Dr.  Bullions',  more  nearly  connected 
with  his  series  than  the  "  Principles  of  English  Grammar." 


OLNEY'S  QUARTO  GEOGRAPHY.  The  Maps  of  this  work  contain  but  little  beside  what 
the  pupil  is  required  to  learn,  consequently  it  facilitates  the  progress  of  the  pupil,  and 
saves  labor  on  the  part  of  the  teacher.  This  Geography  was  prepared  at  the  suggestion 
of  many  teachers,  and  is  already  extensively  introduced  from  preference.  Few  books 
have  proved  so  uniformly  acceptable  for  common  schools. 

OLNEY'S  SCHOOL  GEOGRAPHY  AND  ATLAS.  This  world-renowned  book  is  not 
behind  any  of  its  competitors,  in  point  of  execution  and  accuracy.  The  Atlas  is  probably 
superior  to  any  other,  and  contains  a  Map  of  the  "World  as  known  to  the  Ancients,  besides 
numerous  important  Tables.  The  whole  work  is  as  complete  and  correct  as  a  new  book,  and 
will  continue  to  maintain  its  character,  though  alterations  will  be  avoided  as  far  as  possible. 

OLNEY'S  OUTLINE  MAPS  AND  OLNEY'S  PRIMARY  GEOGRAPHY,  are  intended 
for  young  pupils,  by  the  same  author. 

BENTLEY'S  PICTORIAL  SPELLING  BOOK.  A  beautifully  illustrated  and  highly 
attractive  book  for  children. 

GALLAUDET'S  ILLUSTRATIVE  DEFINER.  The  best  book  for  teaching  the  right  use 
of  words,  and  the  art  of  composition. 

KIRKHAM'S  EXERCISES  IN  ELOCUTION. 

THE  STUDENT'S  PRIMER,  by  J.  S.  DENMAN.  Being  on  a  plan  somewhat  new,  this  Primer 
has  obtained  great  popularity. 

THE  STUDENT'S  SPEAKER,  for  young  pupils. 

THE  STUDENT'S  SPELLING  BOOK,  on  the  Analytical  plan,  by  the  author  of  the  "  Stu- 
dent's Primer." 

THE  WORKS  OF  VIRGIL,  WITH  COPIOUS  NOTES,  <fco. ;  also,  a  Table  of  Reference. 
By  REV.  J.  G.  COOPER,  A.M. 

THE  YOUNG  PUPIL'S  MENTAL  AND  WRITTEN  ARITHMETIC,  by  H.  S.  SCHKLL. 

Com0tock'0  6erU0  of  Books  of  %  Swnce0,  tri?.  : 

INTRODUCTION  TO  NATURAL  PHILOSOPHY,  for  children. 

SYSTEM  OF  NATURAL  PHILOSOPHY,  revised  and  enlarged. 

NEW  ELEMENTS  OF  CHEMISTRY. 

THE  YOUNG  BOTANIST,  for  beginners,  with  cuts. 

ELEMENTS  OF  BOTANY  AND  VEGETABLE  PHYSIOLOGY,  with  cute. 

OUTLINES  OF  PHYSIOLOGY,  both  comparative  and  human. 

(NEW)  ELEMENTS  OF  GEOLOGY. 

ELEMENTS  OF  MINERALOGY. 

NATURAL   HISTORY   OF  BEASTS   AND  BIRDS,  showing  their  comparative 

size,  and  containing  anecdotes,  illustrating  their  habits  and  instincts. 
The  immense  sale  of  Dr.  Comstock's  books,  renders  it  probable  that  they  are  familiar  to 
most  teachers.     They  are  so  admirably  adapted  to  the  school-room,  that  the  "  Philosophy  " 
has  been  republished  in  several  European  countries.      Revised  editions  of  several  of  these 
works  have  been  recently  issued,  including  late  discoveries  and  improvements. 

The  publications  of  P.  W.  <fe  Co.  are  well  printed,  and  neatly  and   substantially  bound. 
They  are  also  furnished  at  low  prices. 

P.  W.  <fe  Co.  have  always  for  sale  an  assortment  of  School  and  Miscellaneous  Books,  Blank 
Books,  Paper,  Pens,  and  Stationery,  suited  to  the  wanta  of  Country  Dealers. 


14  DAY  USE 

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BIOLOGY  LIBRARY 

TEL.  NO.  642-2532 

This  book  is  due  on  the  last  date  stamped  below,  or 

on  the  date  to  which  renewed. 
Renewed  books  are  subject  to  immediate  recall. 


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